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134-606: The Fujita scale ( F-Scale ; / f u ˈ dʒ iː t ə / ), or Fujita–Pearson scale ( FPP scale ), is a scale for rating tornado intensity , based primarily on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determined by meteorologists and engineers after a ground or aerial damage survey , or both; and depending on the circumstances, ground-swirl patterns ( cycloidal marks), weather radar data, witness testimonies, media reports and damage imagery, as well as photogrammetry or videogrammetry if motion picture recording

268-743: A Monsanto plant. Train cars near the plant were blown off the tracks and thrown into the building. The tornado then finally dissipated near Oliver Lake airfield. A total of 18 people were killed during the storm including five people from Fort Wayne when their mini-bus fell 50 feet (15 m) into the Tippecanoe River near Monticello. One passenger did survive the fall. Five others were killed in White County, six in Fulton County and one in Kosciusko County . The National Guard had assisted

402-574: A WHAS-TV Louisville reporter in a special report about the outbreak, 90% of Hanover was destroyed or severely damaged, including the Hanover College campus. Despite the fact that no one was killed or seriously injured at the college, 32 of the college's 33 buildings were damaged, including two that were completely destroyed and six that sustained major structural damage. Hundreds of trees were down, completely blocking every campus road. All utilities were knocked out and communication with those off campus

536-477: A lifecycle that causes the same tornado to change in appearance over time. People in the path of a tornado should never attempt to determine its strength as it approaches. Between 1950 and 2014 in the United States, 222 people have been killed by EF1 tornadoes, and 21 have been killed by EF0 tornadoes. Around 60–70 percent of tornadoes are designated EF1 or EF0, also known as "weak" tornadoes. But "weak"

670-443: A 32-mile (51 km) path. The tornado first moved across the north edge of Hardinsburg , inflicting F3 damage to homes at that location. The tornado quickly became violent as it moved into Meade County , producing F4 damage as it passed north of Irvington , sweeping away numerous homes in this rural area. Vehicles were thrown hundreds of yards from residences and mangled, and a few were completely wrapped around trees. One home that

804-532: A 60-foot (18 m) hill near the Tippecanoe River and heavily damaged several homes immediately afterwards. Soon after the Depauw tornado lifted, the Hanover/Madison F4 tornado formed near Henryville and traveled through Jefferson County and leveled many structures in the small towns of Hanover and Madison . A total of 11 people were killed in this storm while an additional 300 were injured. According to

938-635: A U.S. research team succeeded in dropping devices called "turtles" into an F4 tornado, and one measured a pressure drop of more than 100 hectopascals (3.0 inHg) as the tornado passed directly overhead. Still, tornadoes are widely varied, so meteorologists are still researching to determine if these values are typical or not. In 2018, the International Fujita scale was created by the European Severe Storms Laboratory as well as other various European meteorological agencies. Unlike

1072-645: A broad region from eastern Mississippi to southern Tennessee . These storms, forming after 23:00 UTC, produced some of the most powerful tornadoes of the outbreak, including a large and long-tracked F4 that struck the western and central portions of Alabama , tracking for just over 110 miles (180 km), two F5s that both slammed into Tanner , causing extensive fatalities, an extremely potent F5 that devastated Guin in Alabama, and multiple violent, deadly tornadoes that affected and caused fatalities in Tennessee. Michigan

1206-520: A distance of 121 miles (195 km). Meanwhile, by 00:00 UTC the southern half of the first convective band became indistinguishable from new convection that had formed farther south over Alabama and Tennessee in connection with convective band two. In this area, increasing west-southwesterly wind shear at all levels of the troposphere, juxtaposed over near-parallel outflow boundaries , allowed successive supercells, all producing strong, long-tracked tornadoes, to develop unconstrained by their outflow in

1340-569: A fatality) in the U.S. back to 1880. The Fujita scale was adopted in most areas outside of the United Kingdom . On February 1, 2007, the Fujita scale was decommissioned, and the Enhanced Fujita Scale was introduced in the United States. The new scale more accurately matches wind speeds to the severity of damage caused by the tornado. Though each damage level is associated with a wind speed,

1474-556: A historic 409-acre (1.66 km ) municipal park located at Eastern Parkway and Cherokee Road, had thousands of mature trees destroyed. A massive re-planting effort was undertaken by the community in the aftermath of the tornado. Dick Gilbert, a helicopter traffic reporter for radio station WHAS-AM , followed the tornado through portions of its track including when it heavily damaged the Louisville Water Company's Crescent Hill pumping station, and gave vivid descriptions of

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1608-407: A major risk in the region's mountainous terrain. In Alderson, West Virginia , "tornado-like winds" caused extensive damage to homes and businesses primarily along WV 3 , some of which had their roof torn off. Many trees and power lines were downed leaving more than 7,000 people without electricity. On April 5, Georgia Governor Jimmy Carter declared 13 counties as disaster areas and put in

1742-402: A means to differentiate tornado intensity and path area, assigned wind speeds to damage that were, at best, educated guesses. Fujita and others recognized this immediately and intensive engineering analysis was conducted through the rest of the 1970s. This research, as well as subsequent research, showed that tornado wind speeds required to inflict the described damage were actually much lower than

1876-543: A mile wide as it tore through the William B. Bankhead National Forest , flattening a huge swath of trees. Surveyors noted that timber damage was equally severe at all elevations in this area, with numerous trees snapped both along exposed ridges and in deep gorges. So many trees were snapped in this area that the tornado path was visible from satellite. The tornado finally dissipated south of Basham after destroying 546 structures. The same supercell then re-strengthened and produced

2010-555: A moderate-sized tornado, then intensified while moving northeast at about 50 mph (80 km/h). The tornado exhibited a multiple-vortex structure and became very large as it approached town. The massive tornado slammed into the western part of Xenia, completely flattening the Windsor Park and Arrowhead subdivisions at F5 intensity, and sweeping away entire rows of brick homes with little debris left behind in some areas. Extensive wind-rowing of debris occurred in nearby fields. When

2144-624: A new band of scattered thunderstorms developed at 15:00 UTC over eastern Arkansas and Missouri; over the next four hours, this band became the focus for several intense supercells, starting in eastern Illinois and southern Indiana. In the wake of the MCS, backing low-level winds, rapid diurnal destabilization, and perhaps cool, mid-level advection had occurred over the warm sector, weakening the convective inhibition (CINH) layer, and favorable wind profiles bolstered helicity to over 230 m /s²—a combination of factors conducive to tornadogenesis . Consequently,

2278-558: A new fire station was completely leveled. The fireman on duty at the time took shelter in a nearby large culvert, and survived without injury. The Walker County Library and the Jasper First Methodist Church were also damaged. The tornado crossed Lewis Smith Lake and moved across the south side of Cullman at 7:40 pm. Multiple homes and shopping centers were damaged or destroyed in the area, resulting in one death and 36 injuries. The tornado finally dissipated northeast of Cullman

2412-450: A new tornado just south of the town of Decatur . The Guin tornado was originally believed by Fujita to have had a 132 miles (212 km) long path, that went all the way from Vernon , to the small town of Hytop , just a few miles south of the Tennessee state line. However, the 46.5 miles (74.8 km) section of the original path, from Decatur to Hytop , was determined later to be from

2546-571: A request to President Nixon for federal aid, citing damage in excess of $ 15.5 million. Service centers were opened at two National Guard Armories, one in Dalton and the other in Calhoun , as well as a church in Dawsonville . The National Guard provided four-wheel drive vehicles for search and rescue efforts. West Virginia Governor Moore declared 14 counties as disaster areas by April 5 and requested

2680-539: A series of tornadoes that earlier struck portions of southern Indiana from north of Brandenburg, Kentucky , into southwest Ohio. This tornado was witnessed on television by thousands of people, as WCPO aired the tornado live during special news coverage of the tornadoes. It was also noted for the rarity in that its path was in parts of three states. It began shortly before 4:30 pm CDT or 5:30 pm EDT in southeastern Indiana in Ohio County north of Rising Sun near

2814-470: A short time later. In total, the storm took three lives, but injured one hundred and fifty residents of Jasper or Cullman. Five hundred buildings were destroyed, with nearly four hundred other buildings severely damaged. At the same time, a third supercell was crossing the state line near the track of the previous two. While rescue efforts were underway to look for people under the destroyed structures, few were aware that another violent tornado would strike

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2948-759: A single 24-hour period, just behind the 2011 Super Outbreak . It was also the most violent tornado outbreak ever recorded, with 30 violent (F4 or F5 rated) tornadoes confirmed. From April 3–4, 1974, there were 148 tornadoes confirmed in 13 U.S. states and the Canadian province of Ontario . In the United States, tornadoes struck Illinois , Indiana , Michigan , Ohio , Kentucky , Tennessee , Alabama , Mississippi , Georgia , North Carolina , Virginia , West Virginia , and New York . The outbreak caused roughly $ 600 million USD (equivalent to $ 3.71 billion in 2023) in damage. The outbreak extensively damaged approximately 900 sq mi (2,331 km ) along

3082-580: A small distance. Exiting Brandenburg, the tornado crossed into Indiana producing F4 damage there before dissipating. The same storm would later produce tornadoes in the Louisville metro area. When the tornado struck on April 3, 1974, many of the Brandenburg residents at that time had also experienced a major flood of the Ohio River that affected the area in 1937 as well as numerous other communities along

3216-568: A tornado family that moved from Illinois to Michigan for 260 miles) during the late afternoon hours. This tornado produced the longest damage path recorded during the 1974 Super Outbreak, on a southwest to northeast path that nearly crossed the entire state of Indiana. According to most records (including the presented map of north Indiana), this tornado formed just southwest of Otterbein in northeast Warren County in west central Indiana, and ended in LaGrange County just northwest of Valentine –

3350-493: A tornado rated F4 based on damage with a path length of 63 miles (101 km) and a path width of 800 yards (730 m) would be rated F,P,P 4,4,4. Use of the Pearson scales was not widespread, however, and it remained more common to simply list a tornado's path length and path width directly. For purposes such as tornado climatology studies, Fujita scale ratings may be grouped into classes. The Fujita scale, introduced in 1971 as

3484-402: A total combined path length of 2,600 mi (4,184 km). At one point, as many as 15 separate tornadoes were occurring simultaneously. The 1974 Super Outbreak was the first tornado outbreak in recorded history to produce more than 100 tornadoes in under a 24-hour period, a feat that was not repeated globally until the 1981 United Kingdom tornado outbreak and in the United States until

3618-444: A total distance of about 121 miles (195 km). Further analysis by Ted Fujita indicated that at the start of the tornado path near Otterbein, downburst winds (also called "twisting downburst") disrupted the tornado's inflow which caused it to briefly dissipate before redeveloping near Brookston in White County at around 4:50 pm EDT and then traveled for 109 miles (175 km). It also struck portions of six other counties, with

3752-599: A total loss of the affected structure. Well-built homes are reduced to a short pile of medium-sized debris on the foundation. Homes with poor or no anchoring are swept completely away. Large, heavy vehicles, including airplanes , trains, and large trucks, can be pushed over, flipped repeatedly, or picked up and thrown. Large, healthy trees are entirely debarked and snapped off close to the ground or uprooted altogether and turned into flying projectiles. Passenger cars and similarly sized objects can be picked up and flung for considerable distances. EF4 damage can be expected to level even

3886-598: A very severe thunderstorm early in the afternoon that, while not producing a tornado, was the costliest storm to hit the city up to that time. By 19:50 UTC, supercells producing F3 tornadoes hit the Decatur and Normal areas in Illinois. As thunderstorms moved into the warmer, moister air mass over eastern Illinois and Indiana, they produced longer-lived tornadoes—one of which began near Otterbein and ended near Valentine in Indiana,

4020-446: A woman was crushed by a school bus that flew into a ditch she was sheltering in. The tornado had a peak width of 700–1,760 yards (640–1,610 m). The tornado that struck the city of Xenia, Ohio stands as the deadliest individual tornado of the 1974 Super Outbreak, killing 32 people and destroying a significant portion of the town. The tornado formed near Bellbrook, Ohio , southwest of Xenia, at about 4:30 pm EDT. It began as

4154-677: Is a relative term for tornadoes, as even these can cause significant damage. F0 and F1 tornadoes are typically short-lived; since 1980, almost 75 percent of tornadoes rated weak stayed on the ground for 1 mile (1.6 km) or less. In this time, though, they can cause both damage and fatalities. EF0 (T0–T1) damage is characterized by superficial damage to structures and vegetation. Well-built structures are typically unscathed, though sometimes sustaining broken windows, with minor damage to roofs and chimneys . Billboards and large signs can be knocked down. Trees may have large branches broken off and can be uprooted if they have shallow roots. Any tornado that

Fujita scale - Misplaced Pages Continue

4288-423: Is about 250 feet (76 m) across, and travels about one mile (1.6 km) before dissipating. However, tornado behavior is variable; these figures represent statistical probabilities only. Two tornadoes that look almost the same can produce drastically different effects. Also, two tornadoes that look very different can produce similar damage, because tornadoes form by several different mechanisms and also follow

4422-686: Is available. The Fujita scale was replaced with the Enhanced Fujita scale (EF-Scale) in the United States in February 2007. In April 2013, Canada adopted the EF-Scale over the Fujita scale along with 31 "Specific Damage Indicators" used by Environment Canada (EC) in their ratings. The scale was introduced in 1971 by Ted Fujita of the University of Chicago , in collaboration with Allen Pearson , head of

4556-498: Is confirmed, but causes no damage (i.e., remains in open fields) is normally rated EF0, as well, even if the tornado had winds that would give it a higher rating. Some NWS offices, however, have rated these tornadoes EFU (EF-Unknown) due to the lack of damage. EF1 (T2–T3) damage has caused significantly more fatalities than those caused by EF0 tornadoes. At this level, damage to mobile homes and other temporary structures becomes significant, and cars and other vehicles can be pushed off

4690-478: The 2011 Super Outbreak . In 2023, tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank various tornado outbreaks. The 1974 Super Outbreak received an OIS of 578, making it the most intense tornado outbreak in recorded history. A powerful springtime low pressure system developed across the North American Interior Plains on April 1 . While moving into

4824-510: The Capshaw and Harvest areas. Numerous homes in Harvest and surrounding rural areas of the county were swept completely away and scattered, and extensive wind-rowing of debris was noted. A bathtub from one residence was found deeply embedded into the ground. Past Harvest, the tornado abruptly dissipated northeast of town, having a peak width of 500 yards. While tornadoes were causing devastation in

4958-550: The Gulf Coast dissipated and then redeveloped northward over the Ohio River valley. Consequently, CAPE levels in the region rose to 1,000 J/kg . However, a warm temperature plume in the elevated mixed layer kept thunderstorms from initiating at the surface. Meanwhile, a large mesoscale convective system (MCS) that had developed overnight in Arkansas continued to strengthen due to strong environmental lapse rates . Later in

5092-529: The Mississippi and Ohio Valley areas, a surge of unusually moist air intensified the storm further, while there were sharp temperature contrasts between both sides of the system. Officials at NOAA and in the National Weather Service forecast offices were expecting a severe weather outbreak on April 3, but not to the extent that ultimately occurred. Several F2 and F3 tornadoes had struck portions of

5226-614: The Ohio River . It then traveled through Boone County, Kentucky , producing F4 damage in the Taylorsport area before crossing the Ohio River a second time into Ohio . Here, the tornado reached F5 intensity as it slammed into Sayler Park . The first area of town hit was the Morehead Marina, where numerous boats were thrown and destroyed. A large floating restaurant barge at this location was lifted, ripped from its moorings, and flipped by

5360-514: The Oklahoma City metropolitan area ). Around 7 p.m., they recorded one measurement of 301 ± 20 miles per hour (484 ± 32 km/h), 50 miles per hour (80 km/h) faster than the previous record. Though this reading is just short of the theoretical F6 rating, the measurement was taken more than 100 feet (30 meters) in the air, where winds are typically stronger than at the surface. In rating tornadoes, only surface wind speeds or

5494-519: The Tennessee River into Limestone County as a large waterspout , the tornado flattened a ¾-mile–wide swath of trees on the opposite bank. Ground scouring occurred in this area, as reddish soil was dug up and plastered against trees. The storm then slammed into Tanner, where many homes were swept away, vehicles were tossed, shrubbery was debarked, and Lawson's Trailer Park sustained major damage. The tornado then continued into Madison County and struck

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5628-476: The Tornado and Storm Research Organization (TORRO) , was developed in 1974 and published a year later. The TORRO scale has 12 levels, which cover a broader range with tighter graduations. It ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. T0–T1 roughly corresponds to F0, T2–T3 to F1, and so on. While T10–T11 would be roughly equivalent to F5, the highest tornado rated to date on

5762-471: The 1960s) literature, such as the original Fujita intensity scale developed by Dr. Tetsuya Theodore "Ted" Fujita in the early 1970s. However, one can find accounts (e.g. [1] ; be sure to scroll down) of some remarkable work done in this field by a U.S. Army soldier, Sergeant John Park Finley . In 1971, Dr. Fujita introduced the idea of a scale to measure tornado winds. With the help of colleague Allen Pearson , he created and introduced what came to be called

5896-464: The Appalachians; and an inversion over the same area. These factors allowed the northern part of the MCS to accelerate due to efficient ducting , while the southern part slowed as the boundary layer warmed and moistened. Numerous surface-based supercells began to develop in the southern area, beginning with one that produced an F3 tornado at about 16:30 UTC near Cleveland, Tennessee . Meanwhile,

6030-602: The EF scale wind speeds, but these are biased to United States construction practices. The EF scale also improved damage parameter descriptions. The original scale as derived by Fujita was a theoretical 13-level scale (F0–F12) designed to smoothly connect the Beaufort scale and the Mach number scale. F1 corresponds to the twelfth level of the Beaufort scale, and F12 corresponds to Mach number 1.0. F0

6164-525: The F-scale indicated, particularly for the upper categories. Also, although the scale gave general descriptions of damage a tornado could cause, it gave little leeway for strength of construction and other factors that might cause a building to sustain more damage at lower wind speeds. Fujita tried to address these problems somewhat in 1992 with the Modified Fujita Scale, but by then he was semi-retired and

6298-797: The F3 tornado listed below. Huntsville was affected shortly before 11:00 pm EDT by a strong F3 tornado produced by the same thunderstorm that produced the Guin tornado. This tornado produced heavy damage in the south end of the city, eventually damaging or destroying nearly 1,000 structures. The tornado touched down north of Hartselle and moved northeast toward Huntsville. It first hit the Redstone Arsenal , damaging or destroying numerous buildings at that location. But thanks to early warning from an MP picket line on Rideout Road (now Research Park Boulevard (SR 255) ), there were only seven, relatively minor, injuries. One of

6432-474: The Fujita scale in 1973. The F in F1, F2, etc. stands for Fujita. The scale was based on a relationship between the Beaufort scale and the Mach number scale; the low end of F1 on his scale corresponds to the low end of B12 on the Beaufort scale, and the low end of F12 corresponds to the speed of sound at sea level, or Mach 1. In practice, tornadoes are only assigned categories F0 through F5. The TORRO scale, created by

6566-402: The Fujita scale is effectively a damage scale, and the wind speeds associated with the damage listed are not rigorously verified. The Enhanced Fujita Scale was formulated due to research that suggested that the wind speeds required to inflict damage by intense tornadoes on the Fujita scale are greatly overestimated. A process of expert elicitation with top engineers and meteorologists resulted in

6700-439: The Fujita scale is no longer used. The first observation confirming that F5 winds could occur happened on April 26, 1991. A tornado near Red Rock, Oklahoma , was monitored by scientists using a portable Doppler weather radar , an experimental radar device that measures wind speed. Near the tornado's peak intensity, they recorded a wind speed of 115–120 meters per second (260–270 miles per hour; 410–430 kilometers per hour). Though

6834-536: The Monterey Trailer Park, resulting in major damage at that location. The tornado then became extremely violent as it approached and entered Guin, with multiple areas of F5 damage noted in and around town. The tornado first struck the Guin Mobile Home Plant as it entered the town, completely obliterating the structure. Nothing was left of the plant but a pile of mangled steel beams, and its foundation

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6968-825: The National Severe Storms Forecast Center/NSSFC (currently the Storm Prediction Center /SPC). The scale was updated in 1973, taking into account path length and width. In the United States, starting in the late 1970s, tornadoes were rated soon after occurrence. The Fujita scale was applied retroactively to tornadoes reported between 1950 and the adoption of the scale in the National Oceanic and Atmospheric Administration (NOAA) National Tornado Database. Fujita rated tornadoes from 1916 to 1992 and Tom Grazulis of The Tornado Project retroactively rated all known significant tornadoes (F2–F5 or causing

7102-702: The National Weather Service was not in a position to update to an entirely new scale, so it went largely unenacted. In the United States, on February 1, 2007, the Fujita scale was decommissioned in favor of what scientists believe is a more accurate Enhanced Fujita Scale. The meteorologists and engineers who designed the EF Scale believe it improves on the F-scale on many counts. It accounts for different degrees of damage that occur with different types of structures, both manmade and natural. The expanded and refined damage indicators and degrees of damage standardize what

7236-592: The Ohio Valley and the South in a separate, earlier outbreak on April 1 and 2, which included three killer tornadoes in Kentucky , Alabama , and Tennessee . The town of Campbellsburg , northeast of Louisville, was hard-hit in this earlier outbreak, with a large portion of the town destroyed by an F3. Between the two outbreaks, an additional tornado was reported in Indiana in the early morning hours of April 3, several hours before

7370-473: The TORRO scale was a T8. Some debate exists as to the usefulness of the TORRO scale over the Fujita scale—while it may be helpful for statistical purposes to have more levels of tornado strength, often the damage caused could be created by a large range of winds, rendering it hard to narrow the tornado down to a single TORRO scale category. Research conducted in the late 1980s and 1990s suggested that even with

7504-450: The Tanner tornadoes were rated F5. However, the rating of the second Tanner tornado is still disputed by some scientists; analysis in one publication estimates F3-F4 damage along the entirety of the second storm's path. This was the second state to have been hit by more than two F5 tornadoes during the 1974 Super Outbreak. The fast-moving nighttime tornado that devastated the town of Guin ,

7638-527: The United States and Canada. F5 and EF5 tornadoes are rare. In the United States, they typically only occur once every few years, and account for approximately 0.1 percent of confirmed tornadoes. An F5 tornado was reported in Elie, Manitoba , in Canada, on June 22, 2007. Before that, the last confirmed F5 was the 1999 Bridge Creek–Moore tornado , which killed 36 people on May 3, 1999. Nine EF5 tornadoes have occurred in

7772-528: The United States, in Greensburg, Kansas , on May 4, 2007; Parkersburg, Iowa , on May 25, 2008; Smithville, Mississippi , Philadelphia, Mississippi , Hackleburg, Alabama , and Rainsville, Alabama , (four separate tornadoes) on April 27, 2011; Joplin, Missouri , on May 22, 2011, and El Reno, Oklahoma , on May 24, 2011. On May 20, 2013, a confirmed EF5 tornado again struck Moore, Oklahoma. A typical tornado has winds of 110 miles per hour (180 km/h) or less,

7906-536: The actual wind speeds needed to cause that damage are unknown." Since then, the Enhanced Fujita Scale has been created using better wind estimates by engineers and meteorologists. The six categories are listed here, in order of increasing intensity. In 1973, Allen Pearson added additional path length and path width parameters to the Fujita scale. Under this version, each tornado would be assigned one Fujita scale rating and two Pearson scale ratings. For example,

8040-457: The advent of Doppler radar, scientists relied on educated guesses for tornado wind speed. The only evidence indicating wind speeds found in the tornado was the damage left behind by tornadoes that struck populated areas. Some believed they reach 400 miles per hour (640 kilometers per hour); others thought they might exceed 500 miles per hour (800 km/h), and perhaps even be supersonic . One can still find these incorrect guesses in some old (until

8174-448: The air before obliterating them, flinging the wreckage for miles, and sweeping the foundation clean. Large, steel-reinforced structures such as schools are completely leveled. Tornadoes of this intensity tend to shred and scour low-lying grass and vegetation from the ground. Very little recognizable structural debris is generated by EF5 damage, with most materials reduced to a coarse mix of small, granular particles and dispersed evenly across

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8308-454: The air delivering weather bulletins and storm-related information until well into the early morning hours of April 4. As electrical power had been knocked out to a substantial portion of the city, the radio station became a clearinghouse for vital information and contact with emergency workers, not only in Louisville but across the state of Kentucky due to its 50,000-watt clear-channel signal and

8442-412: The area. The path of the second tornado, which formed at 7:35 pm CDT was 83 miles in length, also had a peak width of 500 yards, and the storm formed along the north bank Tennessee River less than a mile from the path of the earlier storm; with much of its path very closely paralleling its predecessor as it tore through Limestone and Madison Counties. 16 people were killed by this second tornado. Tanner

8576-654: The assistance of the National Guard. President Nixon approved federal aid for Fayette, Greenbriar, Raleigh, and Wyoming Counties on April 11. Total damage from the tornadoes and thunderstorms in the state reached $ 3,655,000, more than half of which was incurred by Raleigh County. The West Virginia State Department of Highways provided two water trucks. The local Red Cross provided $ 3,000 to victims in Fayette County and assisted residents with acquiring supplies and dealing with medical bills. Sightseers traveling to look at

8710-401: The broad base of the trough. The mid-latitude low-pressure center over Kansas continued to deepen to 980 mb (28.94 inHg), and wind speeds at the 850-mb level increased to 50 kn (58 mph) (25.7 m/s (93 km/h)) over portions of Louisiana , Mississippi, and Alabama. Due to significant moisture advection , destabilization rapidly proceeded apace; the warm front near

8844-511: The building was flattened. Upon exiting Xenia, the tornado passed through Wilberforce , heavily damaging several campus and residential buildings of Wilberforce University . Central State University also sustained considerable damage, and a water tower there was toppled. Afterwards, the tornado weakened before dissipating in Clark County near South Vienna , traveling a little over 30 miles (48 km). A total of 32 people lost their lives in

8978-584: The buildings destroyed was a publications center for the Nuclear Weapons Training School on the Arsenal. For months afterwards, portions of classified documents were being returned by farmers in Tennessee and Alabama. Many homes were badly damaged or destroyed as the tornado passed through residential areas of the city, and a school was destroyed as well. Many businesses were also heavily damaged, and numerous trees and power lines were downed throughout

9112-408: The case of violent tornadoes, only a small portion of the path area is of violent intensity; most of the higher intensity is from subvortices . In the United States, 80% of tornadoes are rated EF0 or EF1 (equivalent to T0 through T3). The rate of occurrence drops off quickly with increasing strength; less than 1% are rated as violent (EF4 or EF5, equivalent to T8 through T11). For many years, before

9246-504: The city. The Glenn'll trailer park was completely destroyed by the tornado, and some sources list a fatality occurring at that location. The tornado then reached Monte Sano Mountain , which has an elevation of 1,640 feet (500 m), where additional homes were torn apart. The National Weather Service office at Huntsville Jetplex was briefly "closed and abandoned" due to the severe weather conditions. The tornado eventually dissipated near Jacobs Mountain. Remarkable electrical phenomenon

9380-581: The communities of Capshaw and Harvest were devastated once again. Numerous homes throughout Madison County were swept completely away, with extensive wind-rowing of debris noted once again. Past Harvest, the tornado swept away multiple additional homes in the Hazel Green area. The tornado continued northeastward through rural portions of Madison County before crossing into Tennessee, where major damage and 6 deaths occurred in Franklin and Lincoln Counties before

9514-544: The community 30 minutes apart. The first tornado formed at 6:30 pm CDT in Lawrence County, Alabama and ended 73 minutes later in Madison County, Alabama , killing 28 people. The tornado first touched down near the small community of Mt. Hope , and then tracked into Mt. Moriah, where the tornado rapidly intensified and swept away homes and hurled fleeing vehicles, and where a family of six were killed. Further along

9648-511: The damage as seen from the air. A WHAS-TV cameraman also filmed the tornado when it passed just east of the Central Business District of Louisville. WHAS-AM broke away from its regular programming shortly before the tornado struck Louisville and was on-air live with John Burke, the chief meteorologist at the National Weather Service 's Louisville office at Standiford Field when the tornado first descended. The station remained on

9782-426: The damage caused by EF5 tornadoes represents a disproportionate hazard to life and limb; since 1950 in the United States, only 59 tornadoes (0.1% of all reports) have been designated F5 or EF5, and yet these have been responsible for more than 1300 deaths and 14,000 injuries (21.5 and 13.6%, respectively). 1974 Super Outbreak The 1974 Super Outbreak was the second-largest tornado outbreak on record for

9916-556: The damage clogged up roadways. The Federal Disaster Assistance Administration (later FEMA) indicated that trailers refurbished after the 1972 Buffalo Creek flood would be used to house displaced persons. On April 10, voting on the Disaster Relief Act of 1974 was expedited and passed unanimously in the United States Senate in direct response to the scale of damage from the tornado outbreak. The primary purpose of

10050-447: The damage described at each category. The error manifests itself to an increasing degree as the category increases, especially in the range of F3 through F5. NOAA notes that "precise wind speed numbers are actually guesses and have never been scientifically verified. Different wind speeds may cause similar-looking damage from place to place—even from building to building. Without a thorough engineering analysis of tornado damage in any event,

10184-419: The damage in one 6-block area was particularly extreme, and remarked that "It was just like the ground had been swept clean. It was just as much of a total wipeout as you can have." Surveyor J.B. Elliot noted that the destruction was so complete, that even some of the foundations were "dislodged, and in some cases swept away." A total of 23 people were killed in Guin. The tornado continued past Guin and struck

10318-701: The day, strong daytime heating caused instability to further rise. By 18:00 UTC, CAPE values in excess of 2,500 J/kg were present over the lower Ohio and the Mississippi Valley . As wind speeds in the troposphere increased, Large-scale lifting overspread the warm sector . At the same time, the forward-propagating MCS spread into the Tennessee and Ohio valleys, where it evolved into the first of three main convection bands that produced tornadoes. This first convective band moved rapidly northeast, at times reaching speeds of about 60 kn (69 mph) (30.9 m/s (111 km/h)). However, thunderstorm activity, for

10452-402: The end of a very strong, nearly record-setting La Niña event. The 1973–74 La Niña was just as strong as the 1998–99 La Niña. Despite the apparent connection between La Niña and two of the largest tornado outbreaks in United States history, no definitive linkage exists between La Niña and this outbreak or tornado activity in general. Some tornado myths were soundly debunked (not necessarily for

10586-421: The fact that storms had knocked numerous broadcasting stations in smaller communities, such as Frankfort , off the air. Then-Governor Wendell Ford commended the station's personnel for their service to the community in the time of crisis, and Dick Gilbert later received a special commendation from then-President Richard Nixon for his tracking of the tornado from his helicopter. As the cluster of thunderstorms

10720-798: The final one which crossed through parts of Indiana, Ohio and Kentucky. Thirty-one people were killed in Brandenburg, Kentucky , and 28 died in Guin, Alabama . An F3 tornado also occurred in Windsor, Ontario , Canada , killing nine and injuring 30 others there, all of them at the former Windsor Curling Club. There were 18 hours of nearly continuous tornado activity that ended in Caldwell County, North Carolina , at about 7:00 am on April 4. A total of 319 were killed in 148 tornadoes from April 3 through April 4 and 5,484 were injured. The 1974 Super Outbreak occurred at

10854-554: The first time) by tornado activity during the outbreak. Of the F5 tornadoes produced by the outbreak, the Depauw-Daisy Hill tornado was the first to form, touching down at 3:20 pm local time. It is probably the least-known of the F5 tornadoes in the outbreak as it traveled through rural areas in southern Indiana northwest of Louisville , traversing about 65 miles (105 km) through parts of Perry and Harrison Counties. F5 damage

10988-523: The ground and tossed as projectiles. Wooded areas suffer an almost total loss of vegetation, and some tree debarking may occur. Statistically speaking, EF3 is the maximum level that allows for reasonably effective residential sheltering in place in a first-floor interior room closest to the center of the house (the most widespread tornado sheltering procedure in America for those with no basement or underground storm shelter). EF4 (T8–T9) damage typically results in

11122-593: The ground, and lighter objects can become small missiles , causing damage outside of the tornado's main path. Wooded areas have a large percentage of their trees snapped or uprooted. EF3 (T6–T7) damage is a serious risk to life and limb and the point at which a tornado statistically becomes significantly more destructive and deadly. Few parts of affected buildings are left standing; well-built structures lose all outer and some inner walls. Unanchored homes are swept away, and homes with poor anchoring may collapse entirely. Small vehicles and similarly sized objects are lifted off

11256-509: The ground. The tornado weakened somewhat as it continued northeastward, passing through multiple Cincinnati neighborhoods and destroying numerous homes. Some of the worst affected areas were Bridgetown , Mack , Dent and Delhi . Damage in Delhi was rated as high as F4. The tornado took three lives and injured 210 with 190 of the injuries were in Hamilton County, Ohio alone. It was considered

11390-508: The hallways, were not injured. All but 10 homes in Martinsburg were destroyed; and in the Daisy Hill community homes were completely swept away at F5 intensity. Published photographs of this storm reveal a very wide debris cloud and wall cloud structure, with no visible condensation funnel at times. Overall, six were killed by the storm and 86 were injured. One of the fatalities occurred when

11524-573: The hardest hit being White County and its town of Monticello . Much of the town was destroyed including the courthouse, some churches and cemeteries, 40 businesses and numerous homes as well as three schools. It also heavily damaged the Penn Central bridge over the Tippecanoe River . Overall damage according to the NOAA was estimated at US$ 250 million with US$ 100 million damage in Monticello alone. After

11658-560: The implication of the Fujita scale, tornado winds were notoriously overestimated, especially in significant and violent tornadoes. Because of this, in 2006, the American Meteorological Society introduced the Enhanced Fujita scale , to help assign realistic wind speeds to tornado damage. The scientists specifically designed the scale so that a tornado assessed on the Fujita scale and the Enhanced Fujita scale would receive

11792-401: The moment, remained mostly elevated in nature. By 16:30 UTC, the large MCS began to splinter into two sections: the southern part slowed, lagging into southeast Tennessee, while the northern part accelerated, reaching Pennsylvania by 19:30 UTC. The split was related to several factors, including a band of subsidence over eastern Kentucky and western West Virginia; local downslope winds over

11926-488: The most robustly built homes, making the common practice of sheltering in an interior room on the ground floor of a residence insufficient to ensure survival. A storm shelter, bomb shelter, reinforced basement, or other subterranean shelter can provide substantial safety against EF4 tornadoes. EF5 (T10–T11) damage represents the upper limit of tornado power, and destruction is almost always total. An EF5 tornado pulls well-built, well-anchored homes off their foundations and into

12060-408: The most violent ( F4 and F5 ) tornadoes ever observed in a single tornado outbreak. There were seven F5 tornadoes and 23 F4 tornadoes. More than 100 tornadoes associated with 33 tornado families . The first tornado of the outbreak is disputed, with some sources indicating an isolated F2 in Indiana at 13:30 UTC while Fujita marked the outbreak's onset at 18:10 UTC with an F0 in Illinois. As

12194-503: The most-photographed tornado of the outbreak. This tornado dissipated west of White Oak , but the same thunderstorm activity was responsible for two other tornado touchdowns in the Lebanon and Mason areas. The Mason tornado, which started in the northern Cincinnati subdivisions of Arlington Heights and Elmwood Place , was rated F4 and took two lives, while the Warren County tornado

12328-434: The neighborhoods of Audubon , Cherokee Triangle , Cherokee-Seneca , Crescent Hill , Indian Hills , Northfield , Rolling Fields , and Tyler Park . Numerous homes were destroyed in residential areas, including a few that were leveled. The tornado ended near the junction of Interstates 264 and 71 after killing three people, injuring 207 people, destroying over 900 homes, and damaging thousands of others. Cherokee Park ,

12462-791: The northwesternmost corner of the state, another supercell crossing the Mississippi-Alabama state line produced another violent tornado that touched down in Pickens County before heading northeast for nearly 2 hours towards the Jasper area causing major damage to its downtown as the F4 storm struck. Damage was reported in Cullman from the storm before it lifted. The Jasper tornado first touched near Aliceville , producing scattered damage as it tracked northeastward. The damage became more intense and continuous as

12596-545: The official start of the outbreak. On Wednesday, April 3, severe weather watches already were issued from the morning from south of the Great Lakes , while in portions of the Upper Midwest, snow was reported, with heavy rain falling across central Michigan and much of Ontario. By 12:00 UTC on April 3, a large-scale trough extended over most of the contiguous United States , with several modest shortwaves rotating around

12730-736: The other three scales (Fujita, Enhanced Fujita, and TORRO), the International Fujita scale has overlapping wind speeds within the ratings. The highest tornado rated on the IF scale was the 2021 South Moravia tornado , which was rated an IF4. In the U.S., F0 and F1 (T0 through T3) tornadoes account for 80% of all tornadoes. The rate of occurrence drops off quickly with increasing strength—violent tornadoes (F4/T8 or stronger), account for less than one percent of all tornado reports. Worldwide, strong tornadoes account for an even smaller percentage of total tornadoes. Violent tornadoes are extremely rare outside of

12864-465: The outbreak tracked from central Illinois and the entirety of northern Indiana from 2:47 p.m. – 6:59 p.m. (UTC−05:00), a span of 4 hours and 12 minutes. Eight tornadoes touched down, including the longest-tracked single tornado of the outbreak: the 121 mi (195 km) F4 Monticello tornado. However, that tornado may itself have been composed of three individual F4 tornadoes. This half-mile (0.8 km) wide F4 tornado developed (as part of

12998-426: The portable radar had the uncertainty of ±5–10 metres per second (11–22 mph; 18–36 km/h), this reading was probably within the F5 range, confirming that tornadoes were capable of violent winds found nowhere else on earth. Eight years later, during the 1999 Oklahoma tornado outbreak of May 3, another scientific team was monitoring an exceptionally violent tornado (one which eventually killed 36 people in

13132-572: The rating of F6, but both were later downgraded to F5. Based on aerial photographs of the damage it caused, Fujita assigned the strongest tornado of the 1974 Super Outbreak , which affected Xenia, Ohio, a preliminary rating of F6 intensity ± 1 scale. The 1977 Birmingham–Smithfield F5 tornado's damage was surveyed by Ted Fujita and he "toyed with the idea of rating the Smithfield tornado an F6". In 2001, tornado expert Thomas P. Grazulis stated in his book F5–F6 Tornadoes ; "In my opinion, if there ever

13266-547: The residents in the relief and cleanup efforts and then-Governor Otis Bowen visited the area days after the storm. One of the few consolations from the tornado was that a century-old bronze bell that belonged to the White County Courthouse and served as timekeeper was found intact despite being thrown a great distance. The tornado itself had contradicted a long-time myth that a tornado would "not follow terrain into steep valleys" as while hitting Monticello, it descended

13400-479: The river, including Louisville and Paducah . The Brandenburg tornado is the only tornado to have officially produced documented F5/EF5 damage in the state of Kentucky, with the 1971 Gosser Ridge, Kentucky tornado being rated F5 by the National Oceanic and Atmospheric Administration and the Nuclear Regulatory Commission , before being downgraded to F4 after 2000. The Sayler Park tornado was among

13534-507: The road or flipped. Permanent structures can suffer major damage to their roofs. EF2 (T4–T5) tornadoes are the lower end of "significant" yet are stronger than most tropical cyclones (though tropical cyclones affect a much larger area and their winds take place for much longer duration). Well-built structures can suffer serious damage, including roof loss, and the collapse of some exterior walls may occur in poorly built structures. Mobile homes, however, are destroyed. Vehicles can be lifted off

13668-457: The same ranking. The EF-scale is more specific in detailing the degrees of damage on different types of structures for a given wind speed. While the F-scale goes from F0 to F12 in theory, the EF-scale is capped at EF5, which is defined as "winds ≥200 miles per hour (320 km/h)". In the United States, the Enhanced Fujita scale went into effect on February 2, 2007, for tornado damage assessments and

13802-481: The schoolhouse. The tornado continued northeast and struck the south sides of Atwood and Leesburg , with additional severe damage occurring at both locations. The tornado then crossed Dewart Lake and Lake Wawasee, destroying multiple lakeside homes and trailers. The Wawasee Airport was hard hit, where hangars were destroyed and planes were thrown and demolished. The tornado destroyed several buildings as it passed between Ligonier and Topeka , including Perry School and

13936-750: The second of three convective bands to generate tornadoes. While violent tornado activity increased over the warm sector, a third band of convection developed at about 16:00 UTC and extended from near St. Louis into west-central Illinois. Based upon real-time satellite imagery and model data, differential positive vorticity advection coincided with the left exit region of an upper-level jet streak which reached wind speeds of up to 130 kn (150 mph) (66.9 m/s (241 km/h)), thereby enhancing thunderstorm growth. Storms grew rapidly in height and extent, producing baseball-sized hail by 17:20 UTC in Illinois and, shortly thereafter, in St. Louis, Missouri , which reported

14070-469: The small community of Twin , destroying numerous homes, mobile homes, and businesses at that location, though the damage was less intense than that observed in Guin. Crossing into Winston County , the tornado struck the small community of Delmar , destroying additional homes and killing 5 people. Mobile homes in Delmar were obliterated, with their frames wrapped around trees. Past Delmar, the tornado grew up to

14204-473: The southeast during the morning of April 4. A series of studies by Dr. Tetsuya T. Fujita in 1974–75—which were later cited in a 2004 survey by Risk Management Solutions—found that three-quarters of all tornadoes in the 1974 Super Outbreak were produced by 30 ' families ' of tornadoes—multiple tornadoes spawned in succession by a single thunderstorm cell. The majority of these were long-lived and long-tracked individual supercells. This tornado outbreak produced

14338-427: The storm reached central Xenia at 4:40 pm, apartment buildings, homes, businesses, churches, and schools including Xenia High School were destroyed. Students in the school, practicing for a play, took cover in the main hallway seconds before the tornado dropped a school bus onto the stage where they had been practicing and extensively damaged the school building. Several railroad cars were lifted and blown over as

14472-689: The storm system moved east where daytime heating had made the air more unstable, the tornadoes grew more intense. A tornado that struck near Monticello, Indiana was an F4 and had a path length of 121 miles (195 km), the longest path length of any tornado for this outbreak. A total of 19 people were killed in this tornado. The first F5 tornado of the day struck the city of Depauw, Indiana , at 3:20 pm EDT. It killed 6 and injured 86 others along its 65-mile path, leveling and sweeping away homes in Depauw and Daisy Hill . Seven F5 tornadoes were observed—one each in Indiana, Ohio and Kentucky, three in Alabama and

14606-459: The storms increased in intensity and coverage as they moved into Illinois, Indiana, and northern Kentucky, producing several tornadoes, including the first F5 tornado of the day, at 19:20 UTC, near Depauw, Indiana . Several of the storms to form between 19:20 and 20:20 UTC became significant, long-lived supercells, producing many strong or violent tornadoes, including three F5s at Depauw; Xenia, Ohio ; and Brandenburg, Kentucky . These storms formed

14740-558: The tornado dissipated in Coffee County. Two of the fatalities in Tennessee occurred when a church was destroyed during service. The death toll from the two tornadoes was over 45 and over 400 were injured. Most of the fatalities occurred in and around the Tanner area. Over 1,000 houses, 200 mobile homes and numerous other outbuildings, automobiles, power lines and trees were completely demolished or heavily damaged. The most recent official National Weather Service records show that both of

14874-543: The tornado entered Tuscaloosa County . The tornado continued to strengthen south of Berry , and two people were killed near the Walker County line when a church was destroyed. The tornado tore directly through downtown Jasper at 6:57 PM, resulting in severe damage and at least 100 injuries. Numerous buildings and storefronts were heavily damaged in downtown Jasper, and many streets were blocked with trees and power lines. The Walker County courthouse sustained major damage, and

15008-519: The tornado passed over a moving Penn Central freight train in the center of town. It toppled headstones in Cherry Grove Cemetery, then moved through the length of the downtown business district, passing west of the courthouse (which sustained some exterior damage). Numerous businesses in downtown Xenia were heavily damaged or destroyed, and several people were killed at the A&;W Root Beer stand as

15142-419: The tornado struck Monticello, the tornado reached peak strength and completely leveled several farms northwest of town. The tornado then went on to tear through the west side of Rochester , where businesses were destroyed and homes were completely leveled and swept away. Riddle Elementary School was badly damaged as well. The tornado then struck Talma , destroying most of the town, including a fastening plant and

15276-550: The tornado's damage path. Large, multiple-ton steel frame vehicles and farm equipment are often mangled beyond recognition and tossed miles away or reduced entirely to unrecognizable parts. The official description of this damage highlights the extreme nature of the destruction, noting that "incredible phenomena will occur"; historically, this has included such displays of power as twisting skyscrapers , ripping roofs off of tornado bunkers , leveling entire communities , and stripping asphalt from roadbeds . Despite their relative rarity,

15410-458: The tornado, and about 1,150 were injured in Xenia, several of whom took proper shelter. In addition to the direct fatalities, two Ohio Air National Guardsmen deployed for disaster assistance were killed on April 17 when a fire swept through their temporary barracks in a furniture store. The memorial in downtown Xenia lists 34 deaths, in honor of the two Guardsmen. About 1,400 buildings (roughly half of

15544-439: The tornado. It was later recovered several miles downstream. A nearby house was lifted from its foundation and thrown into the river. At a further inland area of Sayler Park, the tornado maintained F5 intensity as numerous homes were swept away at a hilly area near a lake, with only bare slabs remaining. NWS surveyors noted that a pickup truck in this area was carried a half block over the roofs of five homes before being smashed to

15678-411: The town) were heavily damaged or destroyed. Damage was estimated at US$ 100 million ($ 471.7 million in 2013 dollars). Dr. Ted Fujita and a team of colleagues undertook a 10-month study of the 1974 Super Outbreak. Fujita initially assigned the Xenia tornado a preliminary rating of F6 intensity ± 1 scale, before deeming F6 ratings "inconceivable". The most prolific and longest-lasting tornado family of

15812-445: The track, many homes were swept away near Moulton . A water pump was completely lifted out of a wellhouse along SR 157 in this area. In one case, the destruction was so complete that a witness reported that the largest recognizable objects among scattered debris from an obliterated house were some bed-springs. The tornado crossed into Morgan County, causing additional destruction in rural areas near Hillsboro and Trinity . Crossing

15946-507: The wind speeds indicated by the damage resulting from the tornado, are taken into account. Also, in practice, the F6 rating is not used. While scientists have long theorized that extremely low pressures might occur in the center of tornadoes, no measurements confirm it. A few home barometers had survived close passes by tornadoes, recording values as low as 24 inches of mercury (810 hectopascals), but these measurements were highly uncertain. In 2003,

16080-514: Was also devastated with 18 of the fatalities occurring along Green Street alone. Trees and shrubbery in town were debarked and stripped, extensive wind-rowing of debris occurred, and numerous vehicles were destroyed as well, some of which had nothing left but the frame and tires. A curtain rod was found speared deeply into the trunk of one tree in town. Several tombstones in the Cap Anderson cemetery were toppled and broken, and some were displaced

16214-469: Was an F6 tornado caught on video, it was the Pampa, Texas tornado of 1995 ". In 2023, it was announced by the Storm Prediction Center and National Weather Service Norman, Oklahoma that the 1970 Lubbock tornado was originally rated F6, which was later downgraded to its official rating of F5. Furthermore, the original wind speed numbers have since been found to be higher than the actual speeds required to incur

16348-552: Was available on damage caused by wind, so the original scale presented little more than educated guesses at wind speed ranges for specific tiers of damage. Fujita intended that only F0–F5 be used in practice, as this covered all possible levels of damage to frame homes as well as the expected estimated bounds of wind speeds. He did, however, add a description for F6, which he called an "inconceivable tornado", to allow for wind speeds exceeding F5 and possible advancements in damage analysis that might show it. In total, two tornadoes received

16482-618: Was crossing much of the Ohio Valley and northern Indiana, additional strong storms developed much further south just east of the Mississippi River into the Tennessee Valley and Mississippi. It produced the first deadly tornadoes in Alabama during the early evening hours. Most of the small town of Tanner , located to the west of Huntsville and south of the Limestone County seat of Athens , was destroyed when two F5 tornadoes struck

16616-635: Was nearly impossible. Damage to the campus alone was estimated at US$ 10 million. In Madison alone, where seven of the fatalities took place, about 300 homes were destroyed. The tornado also brushed the community of China causing additional fatalities. The same storm would later strike the Cincinnati area, producing multiple tornadoes, including another F5 tornado. The Brandenburg tornado, which produced F5 damage and took 31 lives, touched down in Breckinridge County around 3:25 pm CDT and followed

16750-470: Was not hit as hard as neighboring states or Windsor, with only one deadly tornado that hit near Coldwater and Hillsdale , killing people in mobile homes; however, thunderstorm downpours caused flash floods, and north of the warm front in the Upper Peninsula , heavy snowfall was reported. Activity in the south moved towards the Appalachians during the overnight hours and produced the final tornadoes across

16884-420: Was observed near the community of Depauw , where numerous farms were leveled. Areas near Palmyra and Borden were also heavily affected by the tornado. Morgan Elementary School in northern Harrison County Indiana was directly hit by the tornado. Four classrooms were destroyed and the roof was removed from the school and placed on the cars of the faculty. Fortunately, the children and faculty, who were huddled in

17018-425: Was partially pushed clean of debris. The town's downtown area was also heavily damaged, with many brick businesses and two churches completely destroyed. Trees in town were debarked, ground scouring occurred, and vehicles were thrown and mangled as well. Residential areas in Guin suffered total devastation, with many homes swept completely away and scattered across fields. According to NWS damage surveyor Bill Herman,

17152-409: Was placed at a position specifying no damage (approximately the eighth level of the Beaufort scale), in analogy to how Beaufort's zeroth level specifies little to no wind. From these wind speed numbers, qualitative descriptions of damage were made for each category of the Fujita scale, and then these descriptions were used to classify tornadoes. At the time Fujita derived the scale, little information

17286-643: Was rated an F2 and injured 10. About an hour after the Brandenburg tornado, the same supercell spawned an F4 tornado that formed in the southwest part of Jefferson County near Kosmosdale . Another funnel cloud formed over Standiford Field Airport , touched down at The Kentucky Fair and Exposition Center , and destroyed the majority of the horse barns at the center and part of Freedom Hall (a multipurpose arena ) before it crossed I-65 , scattering several vehicles on that busy expressway. The tornado continued its 22-mile (35 km) journey northeast where it demolished most of Audubon Elementary School and affected

17420-565: Was reported as the tornado passed through Huntsville, with reports of luminous clouds, ball lightning , and multi-colored flashes and glowing areas in the sky as the storm moved through the city. These aforementioned flashes were more than likely Power Flashes, which are flashes of light caused by arcing electrical discharges from damaged electrical equipment, most often severed power lines. Severe thunderstorms on April 4 brought 1 to 3 in (2.5 to 7.6 cm) of rain to tornado-stricken areas of northwest Georgia. Flash floods were considered

17554-639: Was somewhat ambiguous. It also is thought to provide much better estimates of wind speeds and sets no upper limit on the wind speeds for the highest level, EF5. Environment Canada began using the Enhanced Fujita scale in Canada on April 1, 2013. The U.S. and Canada are the only countries to officially adopt the Enhanced Fujita scale. Tornado intensity Tornadoes vary in intensity regardless of shape, size, and location, though strong tornadoes are typically larger than weak tornadoes. The association with track length and duration also varies, although longer-track (and longer-lived) tornadoes tend to be stronger. In

17688-505: Was swept away sustained total collapse of a poured concrete walk-out basement wall. A news photographer reported that the tornado "left no grass" as it crossed KY 79 in this area, and canceled checks from near Irvington were later found in Ohio. Past Irvington, the tornado tore directly through Brandenburg at F5 intensity, completely leveling and sweeping away numerous homes, some of which were well-built and anchor-bolted. The town's downtown area

17822-412: Was the first community to be hit, and many structures that were left standing after the first tornado were destroyed in the second one. A man injured at Lawson's Trailer Park in the first tornado was taken to a church in the area, which collapsed in the second tornado, killing him. After devastating what was left of Tanner, the tornado continued across rural Limestone County and into Madison County, where

17956-471: Was the longest-duration F5 tornado recorded in the outbreak, and considered to be one of the most violent ever recorded. The Guin Tornado traveled over 79.5 miles (127.9 km), from the town of Vernon, Alabama , to just south of the small town of Basham , before lifting just after 10:30 pm CDT. It formed at around 8:50 pm CDT near the Mississippi-Alabama border, north of the town of Vernon , striking

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