The Missoula floods (also known as the Spokane floods , the Bretz floods , or Bretz's floods ) were cataclysmic glacial lake outburst floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age . These floods were the result of periodic sudden ruptures of the ice dam on the Clark Fork River that created Glacial Lake Missoula . After each ice dam rupture, the waters of the lake would rush down the Clark Fork and the Columbia River , flooding much of eastern Washington and the Willamette Valley in western Oregon . After the lake drained, the ice would reform, creating Glacial Lake Missoula again.
95-735: Stark Street is an east-west-running street in Portland, Oregon , in the United States. The street is named after Benjamin Stark , and is divided as Southeast Stark Street and Southwest Stark Street by the Willamette River . A stretch of Stark Street has been designated Southwest Harvey Milk Street to commemorate LGBTQ rights activist Harvey Milk . On the east side of the Willamette River and in parts of Washington County , Stark Street follows
190-512: A major regional heat wave . The record had been broken for three consecutive days with daytime highs of 108 °F (42 °C) on June 26 and 112 °F (44 °C) on June 27; the previous record of 107 °F (42 °C) was set in July 1965 and matched twice in August 1981. A temperature of 100 °F (38 °C) has been recorded in all five months from May through September. The warmest night of
285-615: A century. During the prehistoric period, the land that would become Portland was flooded after the collapse of glacial dams from Lake Missoula , in what would later become Montana. These massive floods occurred during the last ice age and filled the Willamette Valley with 300 to 400 feet (91 to 122 m) of water. Before American settlers began arriving in the 1800s, the land was inhabited for many centuries by two bands of indigenous Chinook people – the Multnomah and
380-510: A comment on the Komatsu analysis, Brian Atwater and colleagues observed substantial evidence for multiple large floods, including mud cracks and animal burrows in lower layers, which were filled by sediment from later floods. Further, evidence for multiple flood flows up sidearms of Glacial Lake Columbia spread over many centuries has been found. They also pointed out that the discharge point from Lake Columbia varied with time, originally flowing across
475-494: A community-driven series of rallies, campaigns, nonprofits and events designed to address Portland's racial history, leading to a city considered significantly more tolerant than in 1988 at Seraw's death. Missoula floods These floods have been researched since the 1920s. During the last deglaciation that followed the end of the Last Glacial Maximum , geologists estimate that a cycle of flooding and reformation of
570-431: A few degrees. Evening temperatures fall to or below freezing 32 nights per year on average, but very rarely below 18 °F (−8 °C). There are only 2.1 days per year where the daytime high temperature fails to rise above freezing; the mean for the lowest high is at the exact freezing point of 32 °F (0 °C). The lowest overnight temperature ever recorded was −3 °F (−19 °C), on February 2, 1950, while
665-508: A highly active volcano 50 miles (80 km) northeast of the city in Washington state, is easily visible on clear days and is close enough to have dusted the city with volcanic ash after its eruption on May 18, 1980. The rocks of the Portland area range in age from late Eocene to more recent eras. Multiple shallow, active fault lines traverse the Portland metropolitan area. Among them are
760-647: A large number of saloons, bordellos , gambling dens, and boarding houses which were populated with miners after the California Gold Rush , as well as the multitude of sailors passing through the port. By the early 20th century, the city had lost its reputation as a "sober frontier city" and garnered a reputation for being violent and dangerous. Between 1900 and 1930, the city's population tripled from nearly 100,000 to 301,815. During World War II , it housed an "assembly center" from which up to 3,676 people of Japanese descent were dispatched to internment camps in
855-568: A newspaper, the Weekly Oregonian . A major fire swept through downtown in August 1873 , destroying twenty blocks on the west side of the Willamette along Yamhill and Morrison Streets, and causing $ 1.3 million in damage, roughly equivalent to $ 33.1 million today. By 1879, the population had grown to 17,500 and by 1890 it had grown to 46,385. In 1888, the first steel bridge on the West Coast
950-473: A protest to commemorate the one-year anniversary of Floyd's murder caused property damage, and was followed by a number of arrests. Portland lies on top of a dormant volcanic field known as the Boring Lava Field , named after the nearby bedroom community of Boring . The Boring Lava Field has at least 32 cinder cones such as Mount Tabor , and its center lies in southeast Portland. Mount St. Helens ,
1045-424: A reputation as a bastion of counterculture . The city operates with a commission-based government , guided by a mayor and four commissioners, as well as Metro , the only directly elected metropolitan planning organization in the United States. Its climate is marked by warm, dry summers and cool, rainy winters. This climate is ideal for growing roses , and Portland has been called the "City of Roses" for over
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#17331109778341140-432: A single street name on a grid. For example, the 200 block north of Burnside is either NW Davis Street or NE Davis Street throughout the entire city. The six previous addressing sections of Portland, which were colloquially known as quadrants despite there being six, have developed distinctive identities, with mild cultural differences and friendly rivalries between their residents, especially between those who live east of
1235-486: A time, contributing to 157 days on average with measurable (≥0.01 in or 0.25 mm) precipitation annually. Temperatures have reached 90 °F (32 °C) as early as April 30 and as late as October 5, while 80 °F (27 °C) has been reached as early as April 1 and as late as October 21. Thunderstorms are uncommon and tornadoes are very rare, although they do occur. See or edit raw graph data . Portland's cityscape derives much of its character from
1330-427: Is Mount Tabor , a volcanic landform. The 2020 census reported the city as 73.8% White (449,025 people), 8.2% Asian (52,854), 5.8% Black or African American (38,217), 0.9% Native American (7,335), 0.5% Pacific Islander (3,919), and 5.0% from two or more races (69,898). 10.3% were Hispanic or Latino, of any race (72,336). Whites not of Hispanic origin made up 68.8% of the total population. The 2010 census reported
1425-433: Is "PDX", the airport code for Portland International Airport . Other nicknames include Bridgetown, Stumptown, Rip City, Soccer City, P-Town, Portlandia, and the more antiquated Little Beirut. From May 28, 2020, until spring 2021, there were daily protests about the murder of George Floyd by police, and racial injustice. There were instances of looting, vandalism, and police actions causing injuries. One protestor
1520-579: Is approximately 100 miles (160 km) upriver from the Pacific Ocean on the Columbia. Though much of downtown Portland is relatively flat, the foothills of the Tualatin Mountains , more commonly referred to locally as the "West Hills", pierce through the northwest and southwest reaches of the city. Council Crest Park at 1,073 feet (327 m) is often quoted as the highest point in Portland; however,
1615-476: Is largely residential. Downtown district , made up of commercial businesses, museums, skyscrapers , and public landmarks represents a small area within the southwest address section. Portland's South Waterfront area has been developing into a dense neighborhood of shops, condominiums, and apartments starting in the mid-2000s. Development in this area is ongoing. The area is served by the Portland Streetcar ,
1710-577: Is the first new bridge to span the Willamette in Portland since the 1973 opening of the double-decker Fremont Bridge . Other bridges that span the Willamette River in the downtown area include the Burnside Bridge , the Ross Island Bridge (both built 1926), and the double-decker Marquam Bridge (built 1966). Other bridges outside the downtown area include the Sellwood Bridge (built 2016) to
1805-595: Is water. Although almost all of Portland is within Multnomah County , small portions of the city are within Clackamas and Washington counties. Portland has a warm-summer Mediterranean climate ( Köppen Csb), falling just short of a hot-summer Mediterranean climate (Köppen Csa) with cool and rainy winters, and warm and dry summers. This climate is characterized by having overcast, wet, and changing weather conditions in fall, winter, and spring, as Portland lies in
1900-682: The Amazon River ). Alternate estimates for the peak flow rate of the largest flood range up to 17 cubic kilometers per hour. The maximum flow speed approached 36 meters/second (130 km/h or 80 mph). Within the Columbia River drainage basin , detailed investigation of the Missoula floods' glaciofluvial deposits , informally known as the Hanford formation , has documented the presence of Middle and Early Pleistocene Missoula flood deposits within
1995-570: The Clackamas . The Chinook people occupying the land were first documented in 1805 by Meriwether Lewis and William Clark . Before its European settlement, the Portland Basin of the lower Columbia River and Willamette River valleys had been one of the most densely populated regions on the Pacific Coast. Large numbers of pioneer settlers began arriving in the Willamette Valley in the 1840s via
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#17331109778342090-484: The MAX Orange Line and four TriMet bus lines. This former industrial area sat as a brownfield prior to development in the mid-2000s. Southeast Portland is largely residential, and consists of several neighborhoods, including Hawthorne District , Belmont , Brooklyn , and Mount Tabor . Reed College , a private liberal arts college that was founded in 1908, is located within the confines of Southeast Portland as
2185-460: The Oregon Trail with many arriving in nearby Oregon City . A new settlement then emerged ten miles from the mouth of the Willamette River, roughly halfway between Oregon City and Hudson's Bay Company 's Fort Vancouver . This community was initially referred to as "Stumptown" and "The Clearing" because of the many trees cut down to allow for its growth. In 1843 William Overton saw potential in
2280-597: The Portland Hills Fault on the city's west side, and the East Bank Fault on the east side. According to a 2017 survey, several of these faults were characterized as "probably more of a hazard" than the Cascadia subduction zone due to their proximities to population centers, with the potential of producing magnitude 7 earthquakes . Notable earthquakes that have impacted the Portland area in recent history include
2375-523: The Portland metropolitan area , making it the 25th-most populous in the United States. About half of Oregon's population resides within the Portland metro area. Named after Portland, Maine , which is itself named after the English Isle of Portland , the Oregon settlement began to be populated in the 1840s, near the end of the Oregon Trail . Its water access provided convenient transportation of goods, and
2470-636: The Potholes Cataract . Bretz coined the term Channeled Scablands in 1923 to refer to the area near the Grand Coulee , where massive erosion had cut through basalt deposits. Bretz published a paper in 1923 arguing that the Channeled Scablands in Eastern Washington were caused by massive flooding in the distant past. Bretz's view, which was seen as arguing for a catastrophic explanation of
2565-465: The Spokane Valley – Rathdrum Prairie immediately downstream of Glacial Lake Missoula, for which several previous estimates had placed the maximum discharge of 17 × 10 m /s and the total amount of water discharged equal to the maximum estimated volume of Lake Missoula (2184 km ). Neglecting erosion effects, their simulated water flow was based on modern-day topography. Their major findings were that
2660-704: The Spokane floods , in the 1920s. He was researching the Channeled Scablands in Eastern Washington , the Columbia Gorge , and the Willamette Valley of Oregon . Beginning In the summer of 1922, Bretz conducted field research on the Columbia River Plateau for the next seven years. He had been interested in unusual erosion features in the area since 1910 after seeing a newly published topographic map of
2755-553: The Willamette Baseline . In late 2017, activists proposed renaming Southwest Stark Street for gay rights activist Harvey Milk , noting a history of racism and support of slavery by Stark. In June 2018, the city council approved renaming the 13-block stretch of Stark from Southwest 11th Street and Southwest Naito Parkway within Downtown Portland as Southwest Harvey Milk Street. The name change took effect immediately upon
2850-560: The urban heat island effect. Neighborhoods outside of the downtown core, especially in slightly higher elevations near the West Hills and Mount Tabor , can experience a dusting of snow while downtown receives no accumulation at all. The city has experienced a few major snow and ice storms in its past, with extreme totals having reached 44.5 in (113 cm) at the airport in 1949–50 and 60.9 in (155 cm) at downtown in 1892–93. Summers in Portland are warm, dry, and sunny, though
2945-766: The 1940s and 1950s. In 1957, Life magazine published an article detailing the city's history of government corruption and crime, specifically its gambling rackets and illegal nightclubs. The article, which focused on crime boss Jim Elkins , became the basis of a fictionalized film titled Portland Exposé (1957). In spite of the city's seedier undercurrent of criminal activity, Portland enjoyed an economic and industrial surge during World War II. Ship builder Henry J. Kaiser had been awarded contracts to build Liberty ships and aircraft carrier escorts, and chose sites in Portland and Vancouver, Washington , for work yards. During this time, Portland's population rose by over 150,000, largely attributed to recruited laborers. During
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3040-483: The 1960s, an influx of hippie subculture began to take root in the city in the wake of San Francisco 's burgeoning countercultural scene. The city's Crystal Ballroom became a hub for the city's psychedelic culture , while food cooperatives and listener-funded media and radio stations were established. A large social activist presence evolved during this time as well, specifically concerning Native American rights , environmentalist causes, and gay rights . By
3135-474: The 1970s, Portland had well established itself as a progressive city, and experienced an economic boom for the majority of the decade; however, the slowing of the housing market in 1979 caused demand for the city and state timber industries to drop significantly. In the 1990s, the technology industry began to emerge in Portland, specifically with the establishment of companies such as Intel , which brought more than US$ 10 billion in investments in 1995 alone. In
3230-420: The 6.8-magnitude Nisqually earthquake in 2001, and a 5.6-magnitude earthquake that struck on March 25, 1993. Per a 2014 report, over 7,000 locations within the Portland area are at high risk for landslides and soil liquefaction in the event of a major earthquake, including much of the city's west side (such as Washington Park ) and sections of Clackamas County . Portland is 60 miles (97 km) east of
3325-576: The Channeled Scabland landforms were formed mainly by multiple periodic floods or by a single grand-scale cataclysmic flood from late Pleistocene Glacial Lake Missoula or an unidentified Canadian source continued through 1999. Shaw's team of geologists reviewed the sedimentary sequences of the Touchet beds and concluded that the sequences do not automatically imply multiple floods separated by decades or centuries. Rather, they proposed that sedimentation in
3420-476: The Columbia Gorge would be expected to produce higher flow resistance and correspondingly higher floods. The dating for Waitt's proposed separation of layers into sequential floods has been supported by subsequent paleomagnetism studies, which support a 30–40 year interval between depositions of Mount St. Helens' ash, and hence flood events, but do not preclude an up to 60-year interval. Offshore deposits on
3515-466: The Columbia River gorge, it backed up again at the 1 mile (1.6 km) wide narrows near Kalama, Washington . Some temporary lakes rose to an elevation of more than 400 ft (120 m), flooding the Willamette Valley to Eugene, Oregon and beyond. Iceberg-rafted glacial erratics and erosion features are evidence of these events. Lake-bottom sediments deposited by the floods have contributed to
3610-606: The Glacial Lake Missoula basin resulted from jökulhlaups draining into Lake Missoula from British Columbia to the north. Further, Shaw's team proposed the scabland flooding might have partially originated from an enormous subglacial reservoir that extended over much of central British Columbia, particularly including the Rocky Mountain Trench , which may have discharged by several paths, including one through Lake Missoula. This discharge, if occurring concurrently with
3705-635: The Othello Channels, Columbia River Gorge, Channeled Scabland , Quincy Basin, Pasco Basin, and the Walla Walla Valley . Based on the presence of multiple interglacial calcretes interbedded with flood deposits, magnetostratigraphy , optically stimulated luminescence dating, and unconformity truncated clastic dikes , it has been estimated that the oldest of the Pleistocene Missoula floods happened before 1.5 million years ago. Because of
3800-455: The Pacific Ocean at the northern end of Oregon 's most populated region, the Willamette Valley. Downtown Portland straddles the banks of the Willamette River, which flows north through the city center and separates the city's east and west neighborhoods. Less than 10 miles (16 km) from downtown, the Willamette River flows into the Columbia River, the fourth-largest river in the United States, which divides Oregon from Washington state. Portland
3895-680: The Waterville Plateau into Moses Coulee, but later, when the Okanagan lobe blocked that route, eroding the Grand Coulee to discharge there as a substantially lower outlet. The Komatsu analysis does not evaluate the impact of the considerable erosion observed in this basin during the flood or floods. However, the assumption that flood hydraulics can be modeled using modern-day topography is an area that warrants further consideration. Earlier narrower constrictions at places such as Wallula Gap and through
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3990-509: The Willamette River versus west of the river. Portland's addressing sections are North, Northwest, Northeast, South, Southeast, and Southwest (which includes downtown Portland ). The Willamette River divides the city into east and west while Burnside Street , which traverses the entire city lengthwise, divides the north and south. North Portland consists of the peninsula formed by the Willamette and Columbia Rivers, with N Williams Ave serving as its eastern boundary. All addresses and streets within
4085-470: The addition of South Portland, all six addressing sectors (N, NE, NW, S, SE and SW) are now officially known as sextants. The Pearl District in Northwest Portland , which was largely occupied by warehouses, light industry and railroad classification yards in the early to mid-20th century, now houses upscale art galleries , restaurants, and retail stores, and is one of the wealthiest neighborhoods in
4180-534: The agricultural Tualatin Valley via the " Great Plank Road " (the route of current-day U.S. Route 26 ), provided the pioneer city with an advantage over other nearby ports, and it grew very quickly. Portland remained the major port in the Pacific Northwest for much of the 19th century, until the 1890s, when Seattle's deepwater harbor was connected to the rest of the mainland by rail, affording an inland route without
4275-460: The agricultural richness of the Willamette and Columbia Valleys. Glacial deposits overlaid with centuries of windblown sediments ( loess ) have scattered steep, southerly sloping dunes throughout the Columbia Valley, ideal conditions for orchard and vineyard development at higher latitudes. After analysis and controversy, geologists now believe that there were 40 or more separate floods, although
4370-467: The breach of the Lake Missoula ice dam, would have provided significantly larger volumes of water. Further, Shaw and the team proposed that the rhythmic Touchet beds result from multiple pulses or surges within a larger flood. In 2000, a team led by Komatsu simulated the floods numerically with a 3-dimensional hydraulic model. They based the Glacial Lake Missoula discharge rate on the rate predicted for
4465-567: The calculated water depth in each flooded location except for the Spokane Valley–Rathdrum Prairie was shallower than the field evidence showed. For example, their calculated water depth at the Pasco Basin–Wallula Gap transition zone is about 190 m, significantly less than the 280–300 m flood depth indicated by high-water marks. They concluded that a flood of ~10 m /s could not have made the observed high-water marks. In
4560-499: The cities to attract and retain the highest number of college-educated people in the United States. Between 2001 and 2012, Portland's gross domestic product per person grew by fifty percent, more than any other city in the country. The city acquired a diverse range of nicknames throughout its history, though it is most often called "Rose City" or "The City of Roses" (unofficial nickname since 1888, official since 2003). Another widely used nickname by local residents in everyday speech
4655-412: The city are prefixed by N, NW, NE, S, SW or SE with the exception of Burnside Street, which is prefixed with W or E. Starting on May 1, 2020, former Southwest prefix addresses with house numbers on east–west streets leading with zero dropped the zero and the street prefix on all streets (including north–south streets) converted from Southwest to South. For example, the current address of 246 S California St.
4750-432: The city as 76.1% White (444,254 people), 7.1% Asian (41,448), 6.3% Black or African American (36,778), 1.0% Native American (5,838), 0.5% Pacific Islander (2,919), 4.7% belonging to two or more racial groups (24,437) and 5.0% from other races (28,987). 9.4% were Hispanic or Latino, of any race (54,840). Whites not of Hispanic origin made up 72.2% of the total population. In 1940, Portland's African-American population
4845-561: The city proper, Portland has one of the largest Vietnamese populations in America per capita. According to statistics, there are over 4,500 Pacific Islanders in Portland, making up 0.7% of the city's population. There is a Tongan community in Portland, who arrived in the area in the 1970s, and Tongans and Pacific Islanders as a whole are one of the fastest-growing ethnic groups in the Portland area. Portland's population has been and remains predominantly White . In 1940, Whites were over 98% of
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#17331109778344940-467: The city's early establishment as being a " scion of New England ; an ends-of-the-earth home for the exiled spawn of the eastern established elite." In 1889, The Oregonian called Portland "the most filthy city in the Northern States", due to the unsanitary sewers and gutters, and, at the turn of the 20th century, it was considered one of the most dangerous port cities in the world. The city housed
5035-418: The city's population. In 2009, Portland had the fifth-highest percentage of White residents among the 40 largest U.S. metropolitan areas. A 2007 survey of the 40 largest cities in the U.S. concluded Portland's urban core has the highest percentage of White residents. Some scholars have noted the Pacific Northwest as a whole is "one of the last Caucasian bastions of the United States". While Portland's diversity
5130-698: The city. Areas further west of the Pearl District include neighborhoods known as Uptown and Nob Hill, as well as the Alphabet District and NW 23rd Ave., a major shopping street lined with clothing boutiques and other upscale retail, mixed with cafes and restaurants. Northeast Portland is home to the Lloyd District , Alberta Arts District , and the Hollywood District . North Portland is largely residential and industrial. It contains Kelley Point Park ,
5225-815: The coast, as well as the protective nature of the Oregon Coast Range to its west, Portland summers are less susceptible to the moderating influence of the nearby Pacific Ocean. Consequently, Portland occasionally experiences heat waves , with temperatures rising above 90 °F (32 °C) for a few days. However, on average, temperatures reach or exceed 80 °F (27 °C) on only 61 days per year, of which 15 days will reach 90 °F (32 °C) and only 1.3 days will reach 100 °F (38 °C). In 2018 more 90-degree days were recorded than ever before. On June 28, 2021, Portland recorded its all-time record high temperature of 116 °F (47 °C) and its warmest daily low temperature of 75 °F (24 °C) during
5320-461: The council's approval of the ordinance enacting it. This Multnomah County , Oregon state location article is a stub . You can help Misplaced Pages by expanding it . Portland, Oregon Portland ( / ˈ p ɔːr t l ə n d / PORT -lənd ) is the most populous city in the U.S. state of Oregon , located in the Pacific Northwest region. Situated in the northwestern area of
5415-406: The cracks, generating more heat, allowing even more water to flow through the cracks. This feedback cycle eventually weakened the ice dam so much that it could no longer support the pressure of the water behind it. It failed catastrophically. This process is known as a glacial lake outburst flood , and there is evidence that many such events occurred in the distant past. As the water emerged from
5510-551: The direct path of the stormy westerly flow, and warm, dry summers when the North Pacific High reaches its northernmost point in mid-summer. Portland's USDA Plant Hardiness Zone is 8b, with parts of the Downtown area falling into zone 9a. Winters are cool, cloudy, and rainy. The coldest month is December with an average daily high temperature of 46.9 °F (8.3 °C), although overnight lows usually remain above freezing by
5605-450: The displaced workers from the wartime settlement to neighboring Albina . There and elsewhere in Portland, they experienced police hostility, lack of employment, and mortgage discrimination , leading to half the black population leaving after the war. In the 1980s and 1990s, radical skinhead groups flourished in Portland. In 1988, Mulugeta Seraw , an Ethiopian immigrant, was killed by three skinheads. The response to his murder involved
5700-468: The east lies the actively volcanic Cascade Range . On clear days, Mt. Hood and Mt. St. Helens dominate the horizon, while Mt. Adams and Mt. Rainier can also be seen in the distance. According to the United States Census Bureau , the city has an area of 145.09 square miles (375.78 km ), of which 133.43 square miles (345.58 km ) is land and 11.66 square miles (30.20 km )
5795-408: The exact source of the water is still being debated. The peak flow of the floods is estimated to be 27 cubic kilometers per hour (6.5 cubic miles per hour). The maximum flow speed approached 36 meters/second (130 km/h or 80 mph). Up to 1.9×10 joules of potential energy were released by each flood (the equivalent of 4,500 megatons of TNT ). For comparison, this is 90 times more powerful than
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#17331109778345890-525: The fragmentary nature of older glaciofluvial deposits, which have been largely removed by subsequent Missoula floods, within the Hanford formation, the exact number of older Missoula floods, which are known as ancient cataclysmic floods , that occurred during the Pleistocene cannot be estimated with any confidence. Geologist J Harlen Bretz first recognized evidence of the catastrophic floods, which he called
5985-561: The geology, ran against the prevailing view of uniformitarianism , and Bretz's views were initially disregarded. The Geological Society of Washington, D.C , invited the young Bretz to present his previously published research at a January 12, 1927, meeting where several other geologists presented competing theories. Another geologist at the meeting, J.T. Pardee , had worked with Bretz and had evidence of an ancient glacial lake that lent credence to Bretz's theories. Bretz defended his theories, which kicked off an acrimonious 40-year debate over
6080-585: The heartland. It was the first American city to have residents report thus, and the Pacific International Livestock Exposition operated from May through September 10, 1942, processing people from the city, northern Oregon, and central Washington . General John DeWitt called the city the first "Jap-free city on the West Coast." At the same time, Portland became a notorious hub for underground criminal activity and organized crime in
6175-484: The highest point in Portland is on a section of NW Skyline Blvd just north of Willamette Stone Heritage site . The highest point east of the river is Mt. Tabor , an extinct volcanic cinder cone, which rises to 636 feet (194 m). Nearby Powell Butte and Rocky Butte rise to 614 feet (187 m) and 612 feet (187 m), respectively. To the west of the Tualatin Mountains lies the Oregon Coast Range , and to
6270-422: The lake lasted an average of 55 years and that the floods occurred several times over the 2,000 years between 15,000 and 13,000 years ago. U.S. Geological Survey hydrologist Jim O'Connor and Spain 's Museo Nacional de Ciencias Naturales scientist Gerardo Benito have found evidence of at least twenty-five massive floods, the largest discharging about 10 cubic kilometers per hour (2.7 million m³/s, 13 times that of
6365-555: The lap of the West Hills , while the flatter east side extends for roughly 180 blocks until it meets the suburb of Gresham . In 1891 the cities of Portland, Albina , and East Portland were consolidated, creating inconsistent patterns of street names and addresses. It was not unusual for a street name to be duplicated in disparate areas. The "Great Renumbering" on September 2, 1931, standardized street naming patterns and divided Portland into five "general districts." It also changed house numbers from 20 per block to 100 per block and adopted
6460-482: The largest Asian ethnic group in the city, followed by Chinese (1.7%), Filipinos (0.6%), Japanese (0.5%), Koreans (0.4%), Laotians (0.4%), Hmong (0.2%), and Cambodians (0.1%). A small population of Iu Mien live in Portland. Portland has two Chinatowns, with New Chinatown in the ' Jade District ' along SE 82nd Avenue with Chinese supermarkets, Hong Kong style noodle houses, dim sum , and Vietnamese phở restaurants. With about 12,000 Vietnamese residing in
6555-472: The largest of the boulders moved by the flood. He estimated the water flow was 9 cubic miles per hour (38 km /h), more than the combined flow of every river in the world. More recent estimates place the flow rate at ten times the flow of all current rivers combined. The Missoula floods have also been referred to as the Bretz floods in honor of Bretz. As the depth of the water in Lake Missoula increased,
6650-404: The late 1990s, the Portland area was rated the fourth-least affordable place in the United States to purchase a new home. After 2000, Portland experienced significant growth, with a population rise of over 90,000 between the years 2000 and 2014. The city's increasing reputation for culture established it as a popular city for young people, and it was second only to Louisville, Kentucky , as one of
6745-451: The lowest daytime high temperature ever recorded was 14 °F (−10 °C) on December 30, 1968. The average window in which freezing temperatures may occur is between November 15 and March 19, allowing a growing season of 240 days. Annual snowfall in Portland is 4.3 inches (10.9 cm), which usually falls between December and March. The city of Portland avoids snow more frequently than its suburbs, due in part to its low elevation and
6840-453: The many bridges that span the Willamette River downtown, several of which are historic landmarks, and Portland has been nicknamed "Bridgetown" for many decades as a result. Three of downtown's most heavily used bridges are more than 100 years old and are designated historic landmarks: Hawthorne Bridge (1910), Steel Bridge (1912), and Broadway Bridge (1913). Portland's newest bridge in the downtown area, Tilikum Crossing , opened in 2015 and
6935-440: The most powerful nuclear weapon ever detonated, the 50-megaton " Tsar Bomba ". The cumulative effect of the floods was to excavate 210 cubic kilometres (50 cu mi) of loess, sediment, and basalt from the Channeled Scablands of eastern Washington and to transport it downstream. The multiple flood hypothesis was first proposed by R.B. Waitt Jr. in 1980. Waitt argued for a sequence of 40 or more floods. Waitt's proposal
7030-452: The new settlement but lacked the funds to file an official land claim. For 25 cents, Overton agreed to share half of the 640-acre (2.6 km ) site with Asa Lovejoy of Boston . In 1844, Overton sold his remaining half of the claim to Francis W. Pettygrove of Portland, Maine . Both Pettygrove and Lovejoy wished to rename "The Clearing" after their respective hometowns (Lovejoy's being Boston, and Pettygrove's, Portland). This controversy
7125-479: The northeast quadrant of the city continued. Portland's longshoremen racial mix was described as being "lily-white" in the 1960s when the local International Longshore and Warehouse Union declined to represent grain handlers since some were black. Racial Makeup of Portland (2022) Over two-thirds of Oregon's African-American residents live in Portland. As of the 2000 census, three of its high schools (Cleveland, Lincoln and Wilson) were over 70% White, reflecting
7220-576: The northernmost point of the city. It also contains the St. Johns neighborhood, which is historically one of the most ethnically diverse and poorest neighborhoods in the city. Old Town Chinatown is next to the Pearl District in Northwest Portland. In 1890 it was the second largest Chinese community in the United States. In 2017, the crime rate was several times above the city average. This neighborhood has been called Portland's skid row. Southwest Portland
7315-565: The origin of the Scablands. Both Pardee and Bretz continued their research over the next 30 years, collecting and analyzing evidence that led them to identify Lake Missoula as the source of the Spokane flood and creator of the channeled scablands. After Pardee studied the canyon of the Flathead River , he estimated that flood waters above 45 miles per hour (72 km/h) would be required to roll
7410-452: The overall population, while Jefferson High School was 87% non-White. The remaining six schools have a higher number of non-Whites, including Blacks and Asians. Hispanic students average from 3.3% at Wells to 31% at Roosevelt . Portland residents identifying solely as Asian Americans account for 7.1% of the population; an additional 1.8% is partially of Asian heritage. Vietnamese Americans make up 2.2% of Portland's population, and make up
7505-410: The pressure at the bottom of the ice dam increased enough to lower the freezing point of water below the temperature of the ice forming the dam. This allowed liquid water to seep into minuscule cracks present in the ice dam. Over a period of time, the friction from water flowing through these cracks generated enough heat to melt the ice walls and enlarge the cracks. This allowed more water to flow through
7600-593: The rapid growth of the Ku Klux Klan , which became very influential in Oregon politics, culminating in the election of Walter M. Pierce as governor. The largest influxes of minority populations occurred during World War II, as the African American population grew by a factor of 10 for wartime work. After World War II, the Vanport flood in 1948 displaced many African Americans. As they resettled, redlining directed
7695-532: The south. It includes the Lair Hill, Johns Landing and South Waterfront districts and Lewis & Clark College as well as the Riverdale area of unincorporated Multnomah County south of the Portland city limits. In 2018, the city's Bureau of Transportation finalized a plan to transition this part of Portland into South Portland, beginning on May 1, 2020, to reduce confusion by 9-1-1 dispatchers and delivery services. With
7790-487: The south; and the St. Johns Bridge , a Gothic revival suspension bridge built in 1931, to the north. The Glenn L. Jackson Memorial Bridge and the Interstate Bridge provide access from Portland across the Columbia River into Washington state. The Willamette River, which flows north through downtown, serves as the natural boundary between East and West Portland. The denser and earlier-developed west side extends into
7885-472: The state at the confluence of the Willamette and Columbia rivers, it is the county seat of Multnomah County , Oregon's most populous county. As of 2020, Portland's population was 652,503, making it the 26th-most populous city in the United States, the sixth-most populous on the West Coast , and the second-most populous in the Pacific Northwest, after Seattle . Approximately 2.5 million people live in
7980-413: The sunny warm weather is short-lived, from mid-June to early September. June, July, August and September account for a combined 4.19 inches (106 mm) of total rainfall – only 11% of the 36.91 in (938 mm) of annual precipitation. The warmest month is August, with an average high temperature of 82.3 °F (27.9 °C). Because of its inland location 62 miles (100 km) from
8075-468: The timber industry was a major force in the city's early economy. At the turn of the 20th century, the city had a reputation as one of the most dangerous port cities in the world, a hub for organized crime and racketeering . After the city's economy experienced an industrial boom during World War II , its hard-edged reputation began to dissipate. Beginning in the 1960s, it became noted for its growing liberal and progressive political values, earning it
8170-426: The top of the Touchet beds. The two layers of volcanic ash are separated by 1–10 centimetres (0.4–3.9 in) of airborne nonvolcanic silt. The tephra is Mount St. Helens ash that fell in Eastern Washington. By analogy, since there were 40 layers with comparable characteristics at Burlingame Canyon, Waitt argued they all could be considered to have similar separation in deposition time. The controversy about whether
8265-401: The treacherous navigation of the Columbia River. The city had its own Japantown, for one, and the lumber industry also became a prominent economic presence, due to the area's large population of Douglas fir , western hemlock , red cedar , and big leaf maple trees. Portland developed a reputation early in its history as a hard-edged and gritty port town . Some historians have described
8360-444: The year averages 68 °F (20 °C). Spring and fall can bring variable weather including high-pressure ridging that sends temperatures surging above 80 °F (27 °C) and cold fronts that plunge daytime temperatures into the 40s °F (4–9 °C). However, lengthy stretches of overcast days beginning in mid-fall and continuing into mid-spring are most common. Rain often falls as a light drizzle for several consecutive days at
8455-475: Was approximately 2,000 and largely consisted of railroad employees and their families. During the war-time Liberty Ship construction boom, the need for workers drew many Black people to the city. The new influx of Black people settled in specific neighborhoods, such as the Albina district and Vanport . The May 1948 flood which destroyed Vanport eliminated the only integrated neighborhood, and an influx of blacks into
8550-610: Was based mainly on analysis from glacial lake bottom deposits in Ninemile Creek and the flood deposits in Burlingame Canyon. His most compelling argument for separate floods was that the Touchet bed deposits from two successive floods were found to be separated by two layers of volcanic ash ( tephra ), with the ash separated by a fine layer of windblown dust deposits, located in a thin layer between sediment layers ten rhythmites below
8645-561: Was changed from 0246 SW California St. and the current address of 4310 S Macadam Ave. was converted from 4310 SW Macadam Ave. The new South Portland addressing section was approved by the Portland City Council on June 6, 2018 and is bounded by SW Naito Parkway , SW View Point Terrace and the Tryon Creek State Natural Area to the west, SW Clay Street to the north, the Willamette River to the east, and city limits to
8740-450: Was historically comparable to metro Seattle and Salt Lake City, those areas grew more diverse in the late 1990s and 2000s. Portland not only remains White, but migration to Portland is disproportionately White. The Oregon Territory banned African American settlement in 1849. In the 19th century, certain laws allowed the immigration of Chinese laborers but prohibited them from owning property or bringing their families. The early 1920s saw
8835-520: Was killed by an opposing one. Local businesses reported losses totaling millions of dollars as the result of vandalism and looting, according to Oregon Public Broadcasting . Some protests caused injury to protesters and police. In July, federal officers were deployed to safeguard federal property; their presence and tactics were criticized by Oregon officials, who demanded they leave, while lawsuits were filed against local and federal law enforcement alleging wrongful actions by them. On May 25, 2021,
8930-543: Was opened in Portland, the predecessor of the 1912 namesake Steel Bridge that survives today. In 1889, Henry Pittock's wife, Georgiana, established the Portland Rose Society. The movement to make Portland a "Rose City" started as the city was preparing for the 1905 Lewis and Clark Centennial Exposition . Portland's access to the Pacific Ocean via the Willamette and Columbia rivers, as well as its easy access to
9025-526: Was settled with a coin toss that Pettygrove won in a series of two out of three tosses, thereby providing Portland with its namesake. The coin used for this decision, now known as the Portland Penny , is on display in the headquarters of the Oregon Historical Society . At the time of its incorporation on February 8, 1851, Portland had over 800 inhabitants, a steam sawmill, a log cabin hotel, and
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