This list of notable flash floods summarizes the most widely reported events.
Date Fatalities Cause Country Description 240 dam failure England Great Sheffield Flood, Sheffield 2208 dam failure US Johnstown Flood Johnstown, Pennsylvania, Most fatalities from a flash flood in US history. 359 heavy rain Spain Consuegra, Castilla-La Mancha 247 thunderstorm US Heppner Flood of 1903, Oregon, Second-deadliest flash flood in the United States; kills almost a quarter of the town's residents. 8 thunderstorm US Mazuma, Nevada, Postmistress among the dead. Relief efforts include a fund set up by William Randolph Hearst. 21 dam failure US Great Molasses Flood, Boston, wall of molasses from a collapsed distillation storage tank moves through the streets at killing 21, injuring 150 431 dam failure United States St. Francis Dam, San Francisquito Canyon The dam failed catastrophically in 1928, killing at least 431 people in the subsequent flood, in what is considered to have been one of the worst American civil engineering disasters of the 20th century and the third-greatest loss of life in California history. 1 heavy rain New Zealand 1929 New Zealand cyclone, Otago and Canterbury, New Zealand. Flooding in many parts of the South Island, especially around the city of Dunedin, where of rain falls in 24 hours. A railway worker dies in a washout on the line between Dunedin and Ranfurly 21 thunderstorm New Zealand Kopuawhara flash flood of 1938, Māhia Peninsula, New Zealand: a temporary camp for rail workers next to a river is hit by a high wall of water already swollen by heavy rain associated with Typhoon Haikui. 34 heavy rain England Lynmouth Flood 2394 heavy storm The Netherlands, Belgium, England, Scotland North Sea flood of 1953, a combination of a high spring tide and a severe European windstorm over the North Sea causes a storm tide. As a result, the Dutch Delta Works are authorized, an elaborate project to enable emergency closing of the mouths of most estuaries, to prevent flood surges upriver. 0 heavy rain US 1965 Philmont Scout Ranch flash flood, Philmont Scout Ranch, New Mexico 464 heavy rain Portugal rain in 5 hours at up to per hour near Lisbon, Portugal 32 monsoon Malaysia Kuala Lumpur floods 238 dam failure US Black Hills flood, South Dakota, in 6 hours 143 thunderstorm US Big Thompson River flood, Colorado 1800–25,000 dam failure India Machchu-2 dam failed due to heavy upstream rain, washes out the town of Morbi and nearby villages of Gujarat, India. Estimated deaths range from 1800 to 25,000 people. Considered worst flash flood of history. 299 heavy rain Japan maximum rainfall per an hour in Nagayo, Nagasaki, floods, landslides, and bridge, house, buildings collapses occur simultaneously in the suburbs of Nagasaki, Kyushu Island, Japan:ja:長崎大水害 (Japanese language edition). Retrieved 10 October 2019. 10 heavy rain Portugal maximum rate of in 30 minutes near Lisbon, Portugal, with similar intensity of 1967 event; much lower fatalities due to lessons learned 10 heavy rain US The Guadalupe River floods in Texas Hill Country after a series of severe thunderstorms dumps of rainfall in its headwaters basin. Hundreds of people had to be rescued; 10 teenagers at a summer camp lost their lives. 26 heavy rain US Shadyside, Ohio 4 thunderstorm US Duck Creek Floods of 1990 near Davenport, Iowa, 11 thunderstorm US Antelope Canyon, Arizona 63 heavy rain Slovakia Jarovnice, Slovakia. Combination of heavy rain and collapse of dam formed by debris causes flood wave that inundates the unprotected Romani settlement. 31 heavy rain US San Marcos, Texas, rains totaling from 10 heavy rain JapanAccording to Japan Meteorological Agency official confirmed report, a to principation per a single hour, total to principation per twelve hours, following flash floods in Nagoya and surrounding area, another 150 persons are wounded, Japanese government official confirmed report.:ja:東海豪雨 (Japanese language edition). Retrieved 1 August 2021. 6 heavy rain US Jacobs Creek Flood, Kansas Turnpike near Emporia, Kansas 0 heavy rain England Boscastle flood, Cornwall 350 heavy rain Ethiopia Eastern Ethiopia, tens of thousands are displaced 125 heavy rain Ethiopia Southern Ethiopia, hundreds of thousands are displaced 64 Sudan Sudan floods 0 heavy rain US Mount Rainier National Park, Washington 0 thunderstorm US The 12–13 June 2008 floods around Duck Creek in Davenport, Iowa 0 thunderstorm US The 2009 Kentuckiana Flash Flood results from of rain falling in less than an hour near Louisville, Kentucky 31 heavy rain Turkey Turkish flash floods. 10 heavy rain US 2009 Southeastern United States floods included flash flooding around Atlanta, Georgia 100 tropical storm Philippines Metro Manila, primarily Marikina, Taguig, and Pasig; and several municipalities in the provinces of Rizal, Bulacan, and Laguna, taking more than a hundred lives and leaving thousands of affected residents homeless. It also submerges several municipalities under feet deep of water for several weeks. It is caused by Typhoon Ketsana. 37heavy rain Italy Giampilieri, Messina, Sicily. See Also 2009 Messina floods and mudslides Philippines 10–13 October in Northern Luzon causing major landslides in the Cordillera Mountains, and submerging 80% of the province of Pangasinan. 0 heavy rain US In late October, a rainy nor'easter causes several flash floods in Southeast Virginia and injures over 100 people. 122 heavy rain Saudi Arabia More than 122 people die in flash floods that sweep away highways and neighborhoods in the city of Jeddah, Saudi Arabia, caused by heavy rains. 42 heavy rain Portugal 2010 Madeira floods and mudslides: of rain fell in 5 hours, much more than the monthly February average of . 51 people die, 250 are injured, and at least eight people are missing. US April–May: The great Nashville, Tennessee, flood. Water in the Cumberland river rose, flooding downtown Nashville and surrounding areas. 20 heavy rain US The Little Missouri River risse over in only a few hours, 2010 Arkansas floods 0 dam failure US Delhi Dam on Iowa's Maquoketa River breaches after of rainfall. 8,000 people evacuate and chunks of highway break off and are swept down river. Contributed to flooding the Mississippi River in Davenport, Iowa. 1400 monsoon Pakistan Mid–July till mid-August, Pakistan's three provinces are badly affected during the monsoon rains when dams, rivers and lakes overflow, killing at least 1400 people and affecting 3.5 million people. 180 cloud burst India Leh, India. More than 180 people are reported to have died with 400 missing and 300 injured due to flash floods, caused probably due to cloud burst. Injured and stranded public are airlifted by Indian army.Cloudburst In The Leh WorldSnap 7 chemical plant accident Hungary Flood caused by the Ajka alumina plant accident in western Hungary A dam wall collapses, freeing about one million cubic metres (35 million cubic feet) of highly alkaline liquid waste, called red mud, from the Ajkai Timföldgyár alumina plant in Ajka, Veszprém County. The mud is released as a wave, flooding several nearby localities, including the village of Kolontár and the town of Devecser. The flood kills seven persons and the high pH (~13) of the sludge burned several hundred people and devastated more than of ground in the basin of the Danube river. 0 heavy rain West Indies St. Lucia, West Indies: The flood displaces about 500 people and receives immediate assistance from local government and international organizations. No fatalities nor injuries are reported. – 1 heavy rain US Dubuque County, Iowa – Jo Daviess County, IllinoisHistoric Heavy Rain and Flash Flooding in Dubuque and Jo Daviess Counties 07/27-07/28/2011 35 heavy rain Australia 2010–2011 Queensland floods, Australia 172 heavy rain Russia 2012 Russian floods Krasnodarsky krai 89 monsoon Philippines2012 Philippine floods Monsoon enhanced by Typhoon Haikui brings torrential rain and floods to Metro Manila and nearby provinces 101 rain storm Argentina 2013 Argentina floods For five hours, extremely heavy rainfall on northeastern section of Buenos Aires Province, Argentina results in several flash floods that claim the lives of at least 101 people. Greater La Plata is hardest hit with 91 reported deaths, and Greater Buenos Aires reports ten deaths. Is the worst flooding in La Plata's history. 5 heavy rains Canada 2013 Alberta floods Considered by some a 1-in-100 year rain event, this flash flood-like event resulted in catastrophic flooding that was the worst in Alberta recorded history. At least 28 emergency operations centers were activated, 100,000 people were displaced, and damages were estimated at $5 billion. 18heavy rain Italy Cyclone Cleopatra, Northeast Sardinia. See Also 2013 Sardinia floods – 2+ heavy rain USA Alabama, Florida 73 rain storm Afghanistan 2014 Baghlan floods High rainfall contributes to the flash flood that destroyed hundreds of mud homes. 300 monsoon floods India, Pakistan Floods caused by five days of heavy rain kill 300 people. 1 heavy rain US 2015 Philmont Scout Ranch flash flood, Philmont Scout Ranch, New Mexico 0 heavy rain US 2015 Ghost Ranch flash flood, Ghost Ranch, New Mexico 21 rain storms US2015 Utah floods Sudden downpours cause flash flooding of canyons in Hildale, Utah, and Zion National Park, killing 21 people- 13 people in Hildale and a group of 7 canyoners in Zion National Park. 17+rain storms EgyptAlexandria and Nile Delta region of Northern Egypt. Strong rains on 25 October and 4 November cause flash flooding and result in the deaths of at least 17 people, including five electrocuted when a tram power line collapsed into a puddle.Severe flash flooding hits Egypt, at least 17 dead 3rain storms JordanFlash flooding occurs in the Jordanian capital Amman causing 3 deaths when a severe thunderstorm lasts over 30 minutes. 2heavy rain US2016 Maryland flood – A historic and deadly flash flood strikes Ellicott City, Maryland due an estimated of rain falling in the city within only two hours. It is said to have been a "1000-year flood" event by the NWS. 10heavy rain, wildfire burn scar US2017 Payson flash floods A flash flood occurred at a popular swimming hole near Payson, Arizona, the flood kills 10 members of an extended family. 24heavy rainGreece2017 West Attica floods Flash floods occur in the towns of Mandra, Nea Peramos and Megara, towards west of Athens, due to heavy rain. 24 people die due to this disaster along with significant damage to property. 10 heavy rain Israel Heavy rainfall in the Negev desert causes a flash flood in the Tzafit canyon trapping a group of hikers and resulting in 10 fatalities. 1heavy rain US2018 Maryland flood Just two years after a historic and deadly flash flood struck the region, another heavy rain brings around in two hours to Elliccott City, Maryland, resulting in a disaster that is assessed to be much worse than the previous one. This is the second "1000-year flood" event in two years. 0heavy rain USHeavy rainfall causes flash flooding in Houston, Texas, and the surrounding area, causing the cancellation of 4 July festivities. 0heavy rain USHeavy rainfall causes flash flooding in Canton, Ohio, and other parts of Stark County. 11heavy rain ItalyA flash flood in a gorge in the southern Italian region of Calabria kills 11 hikers.Italy: At least 11 killed by flash flood in Calabria gorge 10heavy rain JapanHeavy rainfall, total per an hour, and on twelve hours precipitation, and resulting to flash flooding, landslide around Boso Peninsula, Chiba Prefecture, Japan.:ja:千葉県豪雨 (Japanese language edition). Retrieved 31 October 2019. 302 (50 missing)heavy rain ChinaAccording to China Meteorological Administration official confirmed report, a heavy rain in the past three days by 20 July, including , per a single hour in Zhengzhou, Henan Province, China. According to Chinese government official confirmed report, flood sweeps away many persons and vehicles are stuck in downtown area, and part section of Zhe