Agbome or Abomey [a.bɔ.mɛ] is the capital of the Zou Department of Benin . The commune of Abomey covers an area of 142 square kilometres and, as of 2012, had a population of 90,195 people.
97-553: Abomey houses the Royal Palaces of Abomey , a collection of small traditional houses that were inhabited by the Kings of Dahomey from 1600 to 1900, and which were designated a World Heritage Site by UNESCO in 1985. Abomey was founded in the 17th century as the capital of the Kingdom of Dahomey (1600–1904), on the site of the former village of Kana. Traditional legends state that the town
194-472: A thunderstorm is blown through a mass of stationary, warm, moist air near the outflow boundary, resulting in a "rolling" effect (often exemplified through a roll cloud ). If low level wind shear is strong enough, the rotation can be turned vertically or diagonally and make contact with the ground. The result is a gustnado. They usually cause small areas of heavier rotational wind damage among areas of straight-line wind damage. A dust devil (also known as
291-517: A "rope tornado". When they rope out, the length of their funnel increases, which forces the winds within the funnel to weaken due to conservation of angular momentum . Multiple-vortex tornadoes can appear as a family of swirls circling a common center, or they may be completely obscured by condensation, dust, and debris, appearing to be a single funnel. In the United States, tornadoes are around 500 feet (150 m) across on average. However, there
388-496: A T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler weather radar data, photogrammetry , and ground swirl patterns ( cycloidal marks) may also be analyzed to determine intensity and award a rating. 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 tornadoes tend to be stronger. In
485-441: A block of dark clouds, wider than the distance from the cloud base to the ground. Even experienced storm observers may not be able to tell the difference between a low-hanging cloud and a wedge tornado from a distance. Many, but not all major tornadoes are wedges. Tornadoes in the dissipating stage can resemble narrow tubes or ropes, and often curl or twist into complex shapes. These tornadoes are said to be "roping out", or becoming
582-454: A body of water (as a waterspout), tornadoes can turn white or even blue. Slow-moving funnels, which ingest a considerable amount of debris and dirt, are usually darker, taking on the color of debris. Tornadoes in the Great Plains can turn red because of the reddish tint of the soil, and tornadoes in mountainous areas can travel over snow-covered ground, turning white. Lighting conditions are
679-541: A continuous, deep rumbling, or an irregular sound of "noise". Since many tornadoes are audible only when very near, sound is not to be thought of as a reliable warning signal for a tornado. Tornadoes are also not the only source of such sounds in severe thunderstorms; any strong, damaging wind, a severe hail volley, or continuous thunder in a thunderstorm may produce a roaring sound. Tornadoes also produce identifiable inaudible infrasonic signatures. Unlike audible signatures, tornadic signatures have been isolated; due to
776-462: A few rotations per minute. Steam devils are very rare. They most often form from smoke issuing from a power plant's smokestack. Hot springs and deserts may also be suitable locations for a tighter, faster-rotating steam devil to form. The phenomenon can occur over water, when cold arctic air passes over relatively warm water. The Fujita scale , Enhanced Fujita scale (EF), and International Fujita scale rate tornadoes by damage caused. The EF scale
873-497: A generous donor, financing it under the “PREMA-Abomey programme”. Conservation work and the enhancement of buildings and collections has been implemented since 1992. This work was possible due to funds to an amount of US$ 450,000 arranged through UNESCO trust. Other donors who also contributed to the work were ICCROM's PREMA programme, the Getty Conservation Institute and Sweden . The bas-reliefs that once decorated
970-435: A major factor in the appearance of a tornado. A tornado which is " back-lit " (viewed with the sun behind it) appears very dark. The same tornado, viewed with the sun at the observer's back, may appear gray or brilliant white. Tornadoes which occur near the time of sunset can be many different colors, appearing in hues of yellow, orange, and pink. Dust kicked up by the winds of the parent thunderstorm, heavy rain and hail, and
1067-464: A market-place and a large square containing the barracks. The average thickness of the walls was about 0.5 m ( 1 + 1 ⁄ 2 ft), which maintained cool temperatures inside the palace rooms. Each palace had a distinct design to suit the whims of the kings. The Kpododji through the Honnouwa formed the first interior courtyard of the palace while the second interior courtyard Jalalahènnou
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#17332024281611164-1012: A mesocyclone) waterspouts. Fair weather waterspouts are less severe but far more common, and are similar to dust devils and landspouts . They form at the bases of cumulus congestus clouds over tropical and subtropical waters. They have relatively weak winds, smooth laminar walls, and typically travel very slowly. They occur most commonly in the Florida Keys and in the northern Adriatic Sea . In contrast, tornadic waterspouts are stronger tornadoes over water. They form over water similarly to mesocyclonic tornadoes, or are stronger tornadoes which cross over water. Since they form from severe thunderstorms and can be far more intense, faster, and longer-lived than fair weather waterspouts, they are more dangerous. In official tornado statistics, waterspouts are generally not counted unless they affect land, though some European weather agencies count waterspouts and tornadoes together. A landspout , or dust-tube tornado ,
1261-413: A probe measured a 100- millibar (100 hPa ; 3.0 inHg ) pressure decrease. The pressure dropped gradually as the vortex approached then dropped extremely rapidly to 850 mbar (850 hPa ; 25 inHg ) in the core of the violent tornado before rising rapidly as the vortex moved away, resulting in a V-shape pressure trace. Temperature tends to decrease and moisture content to increase in
1358-504: A process hastened when the French built the new administrative centre of Bohicon immediately to the east. Today, the city is of less importance, but is still popular with tourists and as a centre for crafts . Since 1985, Abomey has maintained its complex of royal palaces as a UNESCO World Heritage Site . The Royal Palaces of Abomey are a group of earthen structures built by the Fon people between
1455-404: A recognizable life cycle which begins when increasing rainfall drags with it an area of quickly descending air known as the rear flank downdraft (RFD). This downdraft accelerates as it approaches the ground, and drags the supercell's rotating mesocyclone towards the ground with it. As the mesocyclone lowers below the cloud base, it begins to take in cool, moist air from the downdraft region of
1552-436: A small cloud of debris near the ground. Tornadoes may be obscured completely by rain or dust. These tornadoes are especially dangerous, as even experienced meteorologists might not see them. Small, relatively weak landspouts may be visible only as a small swirl of dust on the ground. Although the condensation funnel may not extend all the way to the ground, if associated surface winds are greater than 64 km/h (40 mph),
1649-617: A tornado impacts. A tornado may be much stronger than its damage-based rating indicates if its strongest winds occur away from suitable damage indicators, such as in an open field. Outside Tornado Alley , and North America in general, violent tornadoes are extremely rare. This is apparently mostly due to the lesser number of tornadoes overall, as research shows that tornado intensity distributions are fairly similar worldwide. A few significant tornadoes occur annually in Europe, Asia, southern Africa, and southeastern South America. The United States has
1746-707: A tornado touches the surface and returns to the baseline level when the tornado dissipates. In many cases, intense tornadoes and thunderstorms exhibit an increased and anomalous dominance of positive polarity CG discharges. Luminosity has been reported in the past and is probably due to misidentification of external light sources such as lightning, city lights, and power flashes from broken lines, as internal sources are now uncommonly reported and are not known to ever have been recorded. In addition to winds, tornadoes also exhibit changes in atmospheric variables such as temperature , moisture , and atmospheric pressure . For example, on June 24, 2003, near Manchester, South Dakota ,
1843-583: A tornado. Tornadoes normally rotate cyclonically (when viewed from above, this is counterclockwise in the northern hemisphere and clockwise in the southern ). While large-scale storms always rotate cyclonically due to the Coriolis effect , thunderstorms and tornadoes are so small that the direct influence of the Coriolis effect is negligible, as indicated by their large Rossby numbers . Supercells and tornadoes rotate cyclonically in numerical simulations even when
1940-545: A two-story building known as the "cowrie house" or akuehue . Under the twelve kings who succeeded from 1625 to 1900, the kingdom established itself as one of the most powerful of the western coast of Africa . UNESCO had inscribed the palaces on the List of World Heritage Sites in Africa . Following this, the site had to be included under the List of World Heritage in Danger since Abomey
2037-762: A whirlwind) resembles a tornado in that it is a vertical swirling column of air. However, they form under clear skies and are no stronger than the weakest tornadoes. They form when a strong convective updraft is formed near the ground on a hot day. If there is enough low-level wind shear, the column of hot, rising air can develop a small cyclonic motion that can be seen near the ground. They are not considered tornadoes because they form during fair weather and are not associated with any clouds. However, they can, on occasion, result in major damage. Small-scale, tornado-like circulations can occur near any intense surface heat source. Those that occur near intense wildfires are called fire whirls . They are not considered tornadoes, except in
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#17332024281612134-468: A widely accepted theory for how most tornadoes form, live, and die, it does not explain the formation of smaller tornadoes, such as landspouts, long-lived tornadoes, or tornadoes with multiple vortices. These each have different mechanisms which influence their development—however, most tornadoes follow a pattern similar to this one. A multiple-vortex tornado is a type of tornado in which two or more columns of spinning air rotate about their own axes and at
2231-407: Is a tornado not associated with a mesocyclone. The name stems from their characterization as a "fair weather waterspout on land". Waterspouts and landspouts share many defining characteristics, including relative weakness, short lifespan, and a small, smooth condensation funnel that often does not reach the surface. Landspouts also create a distinctively laminar cloud of dust when they make contact with
2328-456: Is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud . It is often referred to as a twister , whirlwind or cyclone , although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward
2425-411: Is a wide range of tornado sizes. Weak tornadoes, or strong yet dissipating tornadoes, can be exceedingly narrow, sometimes only a few feet or couple meters across. One tornado was reported to have a damage path only 7 feet (2.1 m) long. On the other end of the spectrum, wedge tornadoes can have a damage path a mile (1.6 km) wide or more. A tornado that affected Hallam, Nebraska on May 22, 2004,
2522-418: Is also commonly referred to as a "twister" or the old-fashioned colloquial term cyclone . A tornado is a violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud. For a vortex to be classified as a tornado, it must be in contact with both the ground and the cloud base. The term
2619-437: Is no break in activity, this is considered a tornado outbreak (although the term "tornado outbreak" has various definitions). A period of several successive days with tornado outbreaks in the same general area (spawned by multiple weather systems) is a tornado outbreak sequence, occasionally called an extended tornado outbreak. Most tornadoes take on the appearance of a narrow funnel , a few hundred meters (yards) across, with
2716-447: Is not precisely defined; for example, there is disagreement as to whether separate touchdowns of the same funnel constitute separate tornadoes. Tornado refers to the vortex of wind, not the condensation cloud. A tornado is not necessarily visible; however, the intense low pressure caused by the high wind speeds (as described by Bernoulli's principle ) and rapid rotation (due to cyclostrophic balance ) usually cause water vapor in
2813-658: The Abomey town in Benin , formerly the capital of the West African Kingdom of Dahomey . The Kingdom was founded in 1625 by the Fon people who developed it into a powerful military and commercial empire, which dominated trade with European slave traders on the Slave Coast until the late 19th century, to whom they sold their prisoners of war. At its peak the palaces could accommodate up to 8000 people. The King's palace included
2910-668: The Latin tonāre 'to thunder'). The metathesis of the r and o in the English spelling was influenced by the Spanish tornado (past participle of tornar 'to twist, turn,', from Latin tornō 'to turn'). The English word has been reborrowed into Spanish, referring to the same weather phenomenon. Tornadoes' opposite phenomena are the widespread, straight-line derechos ( / d ə ˈ r eɪ tʃ oʊ / , from Spanish : derecho Spanish pronunciation: [deˈɾetʃo] , 'straight'). A tornado
3007-614: The Second Franco-Dahomean War , they seized the Singboji palace. King Béhanzin , the last independent reigning king of Dahomey and the remnants of his army fled north as the French entered the capital on 17 November. The French chose Béhanzin's brother, Goutchili, as the new king. Béhanzin was eventually deported to the Martinique . His successor King Agooli Agbo could rule only until his deportation to Gabon in 1900. In 1960, when
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3104-544: The desiccation of water from the structural remains, and fire extinguishing equipment to aid in the prevention of similar incidents. Restoration works were supported by international organisations upon request by the Benin authorities and the World Heritage Centre . Extensive conservation work, extensions of buildings and collections have been carried out since 1992. The Italian Agency for Development Cooperation has been
3201-459: The equator and are less common at high latitudes . Other tornado-like phenomena that exist in nature include the gustnado , dust devil , fire whirl , and steam devil . Tornadoes occur most frequently in North America (particularly in central and southeastern regions of the United States colloquially known as Tornado Alley ; the United States has by far the most tornadoes of any country in
3298-406: The "funnel cloud" term is strictly defined as a rotating cloud which is not associated with strong winds at the surface, and condensation funnel is a broad term for any rotating cloud below a cumuliform cloud. Tornadoes often begin as funnel clouds with no associated strong winds at the surface, and not all funnel clouds evolve into tornadoes. Most tornadoes produce strong winds at the surface while
3395-422: The Coriolis effect is neglected. Low-level mesocyclones and tornadoes owe their rotation to complex processes within the supercell and ambient environment. Approximately 1 percent of tornadoes rotate in an anticyclonic direction in the northern hemisphere. Typically, systems as weak as landspouts and gustnadoes can rotate anticyclonically, and usually only those which form on the anticyclonic shear side of
3492-513: The Fon people. As reported by UNESCO, on 21 January 2009 the Royal Palaces of Abomey suffered from a fire "which destroyed several buildings." The fire was the most recent disaster to have plagued the site, coming after a powerful tornado damaged the site in 1984. Royal Palaces of Abomey The Royal Palaces of Abomey are 12 palaces spread over an area of 40 hectares (100 acres) at the heart of
3589-681: The French colonel Alfred Dodds to a predecessor of the Musée du quai Branly in Paris, constitute the first permanent restitutions under the new law. Further, a loan of 20 million Euros from the French Development Agency was allocated for a new museum in Abomey . The 26 cultural artifacts were repatriated to Benin and starting in early 2022 were on display at the Benin's Palais de la Marina in Cotonou . The artifacts have been scheduled to travel around
3686-512: The French colonial administration. Its coverage includes all the palaces within an area of 40 ha (99 acres), and particularly the palaces of King Guézo and King Glèlè . The museum has 1,050 exhibits, most of these belonged to the kings who ruled Danhomè. The museum has many exhibits, which represent the culture of the Kingdom of Dahomey. Some of the significant exhibits are appliquéd “king” quilt, traditional drums, and paintings of ceremonies and
3783-560: The RFD also reaches the ground, fanning outward and creating a gust front that can cause severe damage a considerable distance from the tornado. Usually, the funnel cloud begins causing damage on the ground (becoming a tornado) within a few minutes of the RFD reaching the ground. Many other aspects of tornado formation (such as why some storms form tornadoes while others do not, or what precise role downdrafts, temperature, and moisture play in tornado formation) are still poorly understood. Initially,
3880-405: The RFD, now an area of cool surface winds, begins to wrap around the tornado, cutting off the inflow of warm air which previously fed the tornado. The flow inside the funnel of the tornado is downward, supplying water vapor from the cloud above. This is contrary to the upward flow inside hurricanes, supplying water vapor from the warm ocean below. Therefore, the energy of the tornado is supplied from
3977-558: The Royal Palaces of Abomey, Benin from the List of World Heritage in Danger, in July 2007. Today, the palaces are no longer inhabited, but those of King Ghézo and King Glélé house the Historical Museum of Abomey, which illustrates the history of the kingdom and its symbolism through a desire for independence, resistance and fight against colonial occupation. The palaces built by the 12 rulers of
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4074-529: The UK (around 33, 0.00013/km , 0.00034/sq mi per year), although those are of lower intensity, briefer and cause minor damage. Tornadoes kill an average of 179 people per year in Bangladesh, the most in the world. Reasons for this include the region's high population density, poor construction quality, and lack of tornado safety knowledge. Other areas of the world that have frequent tornadoes include South Africa,
4171-501: The air to condense into cloud droplets due to adiabatic cooling . This results in the formation of a visible funnel cloud or condensation funnel. There is some disagreement over the definition of a funnel cloud and a condensation funnel. According to the Glossary of Meteorology , a funnel cloud is any rotating cloud pendant from a cumulus or cumulonimbus, and thus most tornadoes are included under this definition. Among many meteorologists,
4268-457: The audible sound depends on atmospheric conditions and topography. The winds of the tornado vortex and of constituent turbulent eddies , as well as airflow interaction with the surface and debris, contribute to the sounds. Funnel clouds also produce sounds. Funnel clouds and small tornadoes are reported as whistling, whining, humming, or the buzzing of innumerable bees or electricity, or more or less harmonic, whereas many tornadoes are reported as
4365-537: The case of the Tri-State Tornado. A 2007 reanalysis of the path suggests that the tornado may have begun 15 miles (24 km) further west than previously thought. Tornadoes can have a wide range of colors, depending on the environment in which they form. Those that form in dry environments can be nearly invisible, marked only by swirling debris at the base of the funnel. Condensation funnels that pick up little or no debris can be gray to white. While traveling over
4462-544: The case of violent tornadoes, only a small portion of the path is of violent intensity, most of the higher intensity from subvortices . In the United States, 80% of tornadoes are EF0 and EF1 (T0 through T3) tornadoes. The rate of occurrence drops off quickly with increasing strength—less than 1% are violent tornadoes (EF4, T8 or stronger). Current records may significantly underestimate the frequency of strong (EF2-EF3) and violent (EF4-EF5) tornadoes, as damage-based intensity estimates are limited to structures and vegetation that
4559-493: The circulation is considered a tornado. A tornado with a nearly cylindrical profile and relatively low height is sometimes referred to as a "stovepipe" tornado. Large tornadoes which appear at least as wide as their cloud-to-ground height can look like large wedges stuck into the ground, and so are known as "wedge tornadoes" or "wedges". The "stovepipe" classification is also used for this type of tornado if it otherwise fits that profile. A wedge can be so wide that it appears to be
4656-430: The city and the palaces be burned. Providentially, most monuments survived the fire and many palaces have been since restored. Copper and brass plaques adorned the walls. The bas-reliefs were inlaid in walls and pillars. They were made out of earth from ant-hills mixed with palm oil and dyed with vegetable and mineral pigments. They represent one of the most impressive highlights of the palaces, which are now on display in
4753-418: The cloud above. As the RFD completely wraps around and chokes off the tornado's air supply, the vortex begins to weaken, becoming thin and rope-like. This is the "dissipating stage", often lasting no more than a few minutes, after which the tornado ends. During this stage, the shape of the tornado becomes highly influenced by the winds of the parent storm, and can be blown into fantastic patterns. Even though
4850-568: The country and be on display in several museums over the following years, finally landing for permanent display in the Museum of the Epics of Amazons and Kings of Danhomè in Abomey. The decolonization of museums is part of a growing global movement to repatriate cultural property to their country of origin. On 21 January 2009, many of the buildings of the Royal Palaces were destroyed by a bushfire, although it
4947-437: The culture, with human sacrifice as one of the practices. The town where the palaces were built was surrounded by a mud wall with a circumference estimated at 10 kilometres (6 mi), pierced by six gates , and protected by a ditch 1.5 m (5 ft) deep, filled with a dense growth of prickly acacia , the usual defence of West African strongholds. Within the walls were villages separated by fields, several royal palaces,
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#17332024281615044-428: The darkness of night are all factors that can reduce the visibility of tornadoes. Tornadoes occurring in these conditions are especially dangerous, since only weather radar observations, or possibly the sound of an approaching tornado, serve as any warning to those in the storm's path. Most significant tornadoes form under the storm's updraft base , which is rain-free, making them visible. Also, most tornadoes occur in
5141-414: The descending rear flank downdraft (RFD) in a cyclonic supercell. On rare occasions, anticyclonic tornadoes form in association with the mesoanticyclone of an anticyclonic supercell, in the same manner as the typical cyclonic tornado, or as a companion tornado either as a satellite tornado or associated with anticyclonic eddies within a supercell. Tornadoes emit widely on the acoustics spectrum and
5238-524: The efforts of storm spotters . There are several scales for rating the strength of tornadoes. The Fujita scale rates tornadoes by damage caused and has been replaced in some countries by the updated Enhanced Fujita Scale . An F0 or EF0 tornado, the weakest category, damages trees, but not substantial structures. An F5 or EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers . The similar TORRO scale ranges from T0 for extremely weak tornadoes to T11 for
5335-401: The first mesocyclone and associated tornado dissipate, the storm's inflow may be concentrated into a new area closer to the center of the storm and possibly feed a new mesocyclone. If a new mesocyclone develops, the cycle may start again, producing one or more new tornadoes. Occasionally, the old (occluded) mesocyclone and the new mesocyclone produce a tornado at the same time. Although this is
5432-528: The ground for more than 100 km (62 mi). Various types of tornadoes include the multiple-vortex tornado , landspout , and waterspout . Waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non- supercellular tornadoes that develop over bodies of water, but there is disagreement over whether to classify them as true tornadoes. These spiraling columns of air frequently develop in tropical areas close to
5529-479: The ground, due to their differing mechanics from true mesoform tornadoes. Though usually weaker than classic tornadoes, they can produce strong winds which could cause serious damage. A gustnado , or gust front tornado , is a small, vertical swirl associated with a gust front or downburst . Because they are not connected with a cloud base, there is some debate as to whether or not gustnadoes are tornadoes. They are formed when fast-moving cold, dry outflow air from
5626-583: The immediate vicinity of a tornado. Tornadoes often develop from a class of thunderstorms known as supercells. Supercells contain mesocyclones , an area of organized rotation a few kilometers/miles up in the atmosphere, usually 1.6–9.7 km (1–6 miles) across. Most intense tornadoes (EF3 to EF5 on the Enhanced Fujita Scale ) develop from supercells. In addition to tornadoes, very heavy rain, frequent lightning, strong wind gusts, and hail are common in such storms. Most tornadoes from supercells follow
5723-519: The interior of British Columbia , and western New Brunswick are also tornado-prone. Tornadoes also occur across northeastern Mexico. The United States averages about 1,200 tornadoes per year, followed by Canada, averaging 62 reported per year. NOAA's has a higher average 100 per year in Canada. The Netherlands has the highest average number of recorded tornadoes per area of any country (more than 20, or 0.00048/km , 0.0012/sq mi annually), followed by
5820-453: The kingdom of Allada in 1724 and the Kingdom of Whydah in 1727. This resulted in the killing of several prisoners. Many of the prisoners were also sold as slaves at Ouidah , then called Gléwé(puff adder house).These wars marked the beginning of the dominance of Dahomey's slave trade (which was carried out through the port of Whydah with the Europeans . In the 19th century, however, with
5917-421: The kingdom within the cloistered site of Abomey functioned between 1695 and 1900 as the traditional cultural hub of the empire. The first ruler to initiate the building of palaces was King Houegbadja , who had founded the city. According to folklore, the descendants of the royal family of Abomey who built the 12 Royal Palaces are the progeny of Princess Aligbonon of Tado and a panther. Their kingdom existed in
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#17332024281616014-402: The late afternoon, when the bright sun can penetrate even the thickest clouds. There is mounting evidence, including Doppler on Wheels mobile radar images and eyewitness accounts, that most tornadoes have a clear, calm center with extremely low pressure, akin to the eye of tropical cyclones . Lightning is said to be the source of illumination for those who claim to have seen the interior of
6111-718: The long-distance propagation of low-frequency sound, efforts are ongoing to develop tornado prediction and detection devices with additional value in understanding tornado morphology, dynamics, and creation. Tornadoes also produce a detectable seismic signature, and research continues on isolating it and understanding the process. Tornadoes emit on the electromagnetic spectrum , with sferics and E-field effects detected. There are observed correlations between tornadoes and patterns of lightning. Tornadic storms do not contain more lightning than other storms and some tornadic cells never produce lightning at all. More often than not, overall cloud-to-ground (CG) lightning activity decreases as
6208-499: The mid-17th and late 19th Centuries. One of the most famous and historically significant traditional sites in West Africa, the palaces form a UNESCO World Heritage Sites . During the reign of Béhanzin , the palaces covered some 44ha and it was surrounded by a 10 meter high wall reaching 4km in length. Only 2 of the original 12 palace survived the 1892 burning by Béhanzin, Dahomey's last king. The French colonial administration rebuilt
6305-538: The most powerful known tornadoes. The International Fujita scale is also used to rate the intensity of tornadoes and other wind events based on the severity of the damage they cause. Doppler radar data, photogrammetry , and ground swirl patterns ( trochoidal marks) may also be analyzed to determine intensity and assign a rating. The word tornado comes from the Spanish tronada (meaning 'thunderstorm', past participle of tronar 'to thunder', itself in turn from
6402-405: The most tornadoes of any country, nearly four times more than estimated in all of Europe, excluding waterspouts. This is mostly due to the unique geography of the continent. North America is a large continent that extends from the tropics north into arctic areas, and has no major east–west mountain range to block air flow between these two areas. In the middle latitudes , where most tornadoes of
6499-487: The museum and replaced by replicas. Many of the objects exhibited in the museum, which were part of the religious ceremonies conducted by the kings in the past, are used even now by the royal family of Dahome in their religious rites. In recognition of the unique cultural significance of these monuments, UNESCO inscribed the Royal Palaces of Abomey under the List of World Heritage Sites in 1985 under Culture – Criteria IV. The site inscribed consists of two zones namely,
6596-588: The palaces have been restored with special efforts of the Getty Conservation Institute, since 1993; in one palace as many as fifty of the fifty-six bas-reliefs have been conserved with "hands-on" involvement of the members of the Benin Cultural Heritage staff. Many of the artists employed at the palaces came from the Ouémé area. In August 2007, Republic of Benin adopted Law No. 2007-20 of 23 on
6693-470: The palaces which form the principal zone and the Akaba Palace Zone on the north-northwest part of the site; both zones are enclosed within a partially preserved cob walls. The UNESCO inscription states: "From 1625 to 1900 twelve kings succeeded one another at the head of the powerful Kingdom of Abomey. With the exception of King Akaba, who used a separate enclosure, they each had their palaces built within
6790-417: The present-day Bénin attained independence from France, it originally bore the name Dahomey. The official history of the kingdom was recorded and followed through a series of polychrome earthen bas-reliefs . Dahomean culture was deeply rooted in intense reverence for the kings of Dahomey and with great religious significance. Each king was symbolised on a "common appliquéd quilt". Ceremonies were part of
6887-516: The protection of cultural heritage and natural heritage of cultural significance. In 2006, the City of Abomey decreed an urban and planning regulation, which provides a secure framework for the protection of the site. The site of the Royal Palaces of Abomey has always included sacred spaces that are respected by the royal families and populations. The organisation of ritual ceremonies is another manner of appropriate safeguarding. Tornado A tornado
6984-406: The rare case where they connect to a pyrocumulus or other cumuliform cloud above. Fire whirls usually are not as strong as tornadoes associated with thunderstorms. They can, however, produce significant damage. A steam devil is a rotating updraft between 50-and-200-metre wide (160 and 660 ft) that involves steam or smoke. These formations do not involve high wind speeds, only completing
7081-494: The record-holding tornado for path length—the Tri-State Tornado , which affected parts of Missouri , Illinois , and Indiana on March 18, 1925—was on the ground continuously for 219 miles (352 km). Many tornadoes which appear to have path lengths of 100 miles (160 km) or longer are composed of a family of tornadoes which have formed in quick succession; however, there is no substantial evidence that this occurred in
7178-546: The rise of the antislavery movement in Great Britain, King Guézo (1818–1858) initiated agricultural development in the country, which resulted in further economic prosperity of the kingdom achieved through exports of agricultural products such as corn and palm oil . From 1892 to 1894, after the Fon returned to raiding the Ouémé Valley, France declared war on Dahomey . Following a string of decisive French victories during
7275-412: The same cob-wall area, in keeping with previous palaces as regards the use of space and materials. The royal palaces of Abomey are a unique reminder of this vanished kingdom." The Royal Palaces of Abomey were taken off the List of World Heritage Sites in Danger in July 2007. The Abomey Historical Museum is housed in a building built over an area of 2 hectares (5 acres), which was established in 1943 by
7372-520: The same mesocyclone. The satellite tornado may appear to " orbit " the larger tornado (hence the name), giving the appearance of one, large multi-vortex tornado. However, a satellite tornado is a distinct circulation, and is much smaller than the main funnel. A waterspout is defined by the National Weather Service as a tornado over water. However, researchers typically distinguish "fair weather" waterspouts from tornadic (i.e. associated with
7469-400: The same time revolve around a common center. A multi-vortex structure can occur in almost any circulation, but is very often observed in intense tornadoes. These vortices often create small areas of heavier damage along the main tornado path. This is a phenomenon that is distinct from a satellite tornado , which is a smaller tornado that forms very near a large, strong tornado contained within
7566-417: The sounds are caused by multiple mechanisms. Various sounds of tornadoes have been reported, mostly related to familiar sounds for the witness and generally some variation of a whooshing roar. Popularly reported sounds include a freight train, rushing rapids or waterfall, a nearby jet engine, or combinations of these. Many tornadoes are not audible from much distance; the nature of and the propagation distance of
7663-460: The southerly flow to its east. This unique topography allows for frequent collisions of warm and cold air, the conditions that breed strong, long-lived storms throughout the year. A large portion of these tornadoes form in an area of the central United States known as Tornado Alley . This area extends into Canada, particularly Ontario and the Prairie Provinces , although southeast Quebec ,
7760-421: The southern part of the present day Republic of Benin in Abomey. Recorded history is, however, traced to the 17th century to two of their descendants, namely Do-Aklin and Dakodonou . Houegbadja (1645–1685) was the king who established the kingdom on the Abomey plateau and set the legal framework for the kingdom's functioning, political role, rules of succession, and so forth. King Agaja (1718–1740) defeated
7857-409: The storm. The convergence of warm air in the updraft and cool air causes a rotating wall cloud to form. The RFD also focuses the mesocyclone's base, causing it to draw air from a smaller and smaller area on the ground. As the updraft intensifies, it creates an area of low pressure at the surface. This pulls the focused mesocyclone down, in the form of a visible condensation funnel. As the funnel descends,
7954-872: The surface of the Earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern. Tornadoes come in many shapes and sizes, and they are often (but not always) visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than 180 kilometers per hour (110 miles per hour), are about 80 meters (250 feet) across, and travel several kilometers (a few miles) before dissipating. The most extreme tornadoes can attain wind speeds of more than 480 kilometers per hour (300 mph), can be more than 3 kilometers (2 mi) in diameter, and can stay on
8051-421: The tornado has a good source of warm, moist air flowing inward to power it, and it grows until it reaches the "mature stage". This can last from a few minutes to more than an hour, and during that time a tornado often causes the most damage, and in rare cases can be more than 1.6 km (1 mile) across. The low pressured atmosphere at the base of the tornado is essential to the endurance of the system. Meanwhile,
8148-427: The tornado is dissipating, it is still capable of causing damage. The storm is contracting into a rope-like tube and, due to conservation of angular momentum , winds can increase at this point. As the tornado enters the dissipating stage, its associated mesocyclone often weakens as well, as the rear flank downdraft cuts off the inflow powering it. Sometimes, in intense supercells, tornadoes can develop cyclically . As
8245-417: The town and connected it with the coast by a railroad. When UNESCO designated the royal palaces of Abomey as a World Heritage Site in 1985 it stated: From 1993, 50 of the 56 bas-reliefs that formerly decorated the walls of King Glèlè (now termed the " Salle des Bijoux ") have been located and replaced on the rebuilt structure. The bas-reliefs carry an iconographic program expressing the history and power of
8342-434: The visible funnel is still above the ground, so it is difficult to discern the difference between a funnel cloud and a tornado from a distance. Occasionally, a single storm will produce more than one tornado, either simultaneously or in succession. Multiple tornadoes produced by the same storm cell are referred to as a "tornado family". Several tornadoes are sometimes spawned from the same large-scale storm system. If there
8439-488: The war between France and Dahomey. On 24 December, 2020, the French government enacted a new law that allows for the permanent restitution of several cultural objects from French collections to Senegal and the Republic of Benin . Following the 2018 report on the restitution of African cultural heritage , 26 statues that had been looted by French troops during the sacking of the Royal Palaces of Abomey in 1892 and donated by
8536-581: The world occur, the Rocky Mountains block moisture and buckle the atmospheric flow , forcing drier air at mid-levels of the troposphere due to downsloped winds, and causing the formation of a low pressure area downwind to the east of the mountains. Increased westerly flow off the Rockies force the formation of a dry line when the flow aloft is strong, while the Gulf of Mexico fuels abundant low-level moisture in
8633-624: The world). Tornadoes also occur in South Africa , much of Europe (except most of the Alps), western and eastern Australia, New Zealand, Bangladesh and adjacent eastern India, Japan, the Philippines, and southeastern South America (Uruguay and Argentina). Tornadoes can be detected before or as they occur through the use of pulse-Doppler radar by recognizing patterns in velocity and reflectivity data, such as hook echoes or debris balls , as well as through
8730-493: Was by the Logodo . The Ajalala, a unique building, which has many types of openings, is in the second courtyard; the walls have decorations of suggestive images in bas-relief. The palaces of Glèlè and Guézo, which survived the intentional fire of 1894 set by Béhanzin, were restored and they are now part of the museum. The materials used for construction consisted of earth for the foundations, floors and raised structures. The wood work
8827-580: Was an update to the older Fujita scale, by expert elicitation , using engineered wind estimates and better damage descriptions. The EF scale was designed so that a tornado rated on the Fujita scale would receive the same numerical rating, and was implemented starting in the United States in 2007. An EF0 tornado will probably damage trees but not substantial structures, whereas an EF5 tornado can rip buildings off their foundations leaving them bare and even deform large skyscrapers . The similar TORRO scale ranges from
8924-413: Was crossed by bridges that were protected by a garrison . The royal palaces were fortified with a nearly square mudbrick wall that was 20 feet high. The flanks reached almost 1 mile as blockhouses were built on each wall. After several attempts, the French conquered the kingdom on 16 November 1892, prompting King Béhanzin to torch the city and flee northward. Thereafter the town declined in importance,
9021-431: Was founded by Do-Aklin, a son of the king of Allada who ventured north to found his own kingdom; the name is thought to come from Danhomé, also spelled Danxomé, meaning "belly of Dan", Dan being the original chief of the village. Dahomey expanded rapidly in the 1700s, absorbing many of the surrounding kingdoms, and growing rich from the slave trade. In the late 18th century, Abomey was surrounded only by dry ditch which
9118-522: Was hit by a tornado on 15 March 1984, when the royal enclosure and museums, particularly the King Guezo Portico, the Assins Room, King's tomb and Jewel Room were damaged. However, with assistance from several international agencies the restoration and renovation work was completed. Based on the corrective works carried out and reports received on these renovations at Abomey, UNESCO decided to remove
9215-497: Was made with palm , bamboo , iroko and mahogany species. Roof was made of straw and sheet-metal. The bas reliefs functioned as a record book (in the absence of written documents) to record the significant events in the evolution of the Fon people and their empire, relating the military victories and power of each king and documenting the Fon people's myths , customs and rituals . However, in 1892, in defiance of French occupation, King Behanzin (1889–1894) ordered that
9312-485: Was unknown where the fire had originated. The extent of the flames spread rapidly as a result of the Harmattan winds, and demolished the straw roof and framework of several of the surrounding buildings. Tombs belonging to Kings Agonglo and Ghezo and their wives were also destroyed in the flames. Authorities acted swiftly in a state of emergency to discuss plans to restore the dilapidated buildings. Such plans included
9409-488: Was up to 2.5 miles (4.0 km) wide at the ground, and a tornado in El Reno, Oklahoma on May 31, 2013, was approximately 2.6 miles (4.2 km) wide, the widest on record. In the United States, the average tornado travels on the ground for 5 miles (8.0 km). However, tornadoes are capable of both much shorter and much longer damage paths: one tornado was reported to have a damage path only 7 feet (2.1 m) long, while
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