Flash flood

A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and depressions. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields. Flash floods may occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from regular floods by having a timescale of fewer than six hours between rainfall and the onset of flooding.[1] The water that is temporarily available is often used by plants with rapid germination and short growth cycles and by specially adapted animal life.

Main and University, Charlottesville, during flash flood (comparison)
An urban underpass during normal conditions (upper) and after fifteen minutes of heavy rain (lower)
Driving through flash flood
Driving through a flash-flooded road
A flash flood after a thunderstorm in the Gobi, Mongolia


Flash floods can occur under several types of conditions. Flash flooding occurs when it rains rapidly on saturated soil or dry soil that has poor absorption ability. The runoff collects in gullies and streams and, as they join to form larger volumes, often form a fast flowing front of water and debris.

Flash floods most often occur in normally dry areas that have recently received precipitation, but they may be seen anywhere downstream from the source of the precipitation, even many miles from the source. In areas on or near volcanoes, flash floods have also occurred after eruptions, when glaciers have been melted by the intense heat. Flash floods are known to occur in the highest mountain ranges of the United States and are also common in the arid plains of the Southwestern United States. Flash flooding can also be caused by extensive rainfall released by hurricanes and other tropical storms, as well as the sudden thawing effect of ice dams.[2][3] Human activities can also cause flash floods to occur. When dams fail, a large quantity of water can be released and destroy everything in its path.[3]


Canandaigua flood July 23, 2017 barn flooded 4
A flash flood greatly inundates a small ditch, flooding barns and ripping out newly installed drain pipes.

The United States National Weather Service gives the advice "Turn Around, Don't Drown" for flash floods; that is, it recommends that people get out of the area of a flash flood, rather than trying to cross it. Many people tend to underestimate the dangers of flash floods. What makes flash floods most dangerous is their sudden nature and fast-moving water. A vehicle provides little to no protection against being swept away; it may make people overconfident and less likely to avoid the flash flood. More than half of the fatalities attributed to flash floods are people swept away in vehicles when trying to cross flooded intersections.[4] As little as 2 feet (0.61 m) of water is enough to carry away most SUV-sized vehicles.[5] The U.S. National Weather Service reported in 2005 that, using a national 30-year average, more people die yearly in floods, 127 on average, than by lightning (73), tornadoes (65), or hurricanes (16).[6]

In deserts, flash floods can be particularly deadly for several reasons. First, storms in arid regions are infrequent, but they can deliver an enormous amount of water in a very short time. Second, these rains often fall on poorly absorbent and often clay-like soil, which greatly increases the amount of runoff that rivers and other water channels have to handle. These regions tend not to have the infrastructure that wetter regions have to divert water from structures and roads, such as storm drains, culverts, and retention basins, either because of sparse population or poverty, or because residents believe the risk of flash floods is not high enough to justify the expense. In fact, in some areas, desert roads frequently cross a dry river and creek beds without bridges. From the driver's perspective, there may be clear weather, when a river unexpectedly forms ahead of or around the vehicle in a matter of seconds.[7] Finally, the lack of regular rain to clear water channels may cause flash floods in deserts to be headed by large amounts of debris, such as rocks, branches, and logs.

Deep slot canyons can be especially dangerous to hikers as they may be flooded by a storm that occurs on a mesa miles away. The flood sweeps through the canyon; the canyon makes it difficult to climb up and out of the way to avoid the flood.

Significant examples

See also


  1. ^ "Flash Flooding Definition". National Weather Service. Retrieved August 31, 2017.
  2. ^ WeatherEye (2007). "Flash Flood!". Sinclair Acquisition IV, Inc. Archived from the original on 2009-02-27. Retrieved 2009-09-09.
  3. ^ a b National Weather Service Forecast Office Morristown, Tennessee (2006-03-07). "Definitions of flood and flash flood". National Weather Service Southern Region Headquarters. Retrieved 2009-09-09.
  4. ^ "Watches, Warnings & Advisories—Flash Flood Warning". National Weather Service. Archived from the original on 2008-01-11. Retrieved 2007-06-25.
  5. ^ "A Preparedness Guide to flash floods #1 weather-related killer in the United States". U.S. Department of Commerce, National Oceanic and Atmospheric Administration National Weather Service, Federal Emergency Management Agency, American Red Cross. July 1992. Retrieved 2007-06-25.
  6. ^ "Turn Around Don't Drown". Retrieved 2007-06-25.
  7. ^ McGuire, Thomas (2004). "Weather Hazards and the Changing Atmosphere" (PDF). Earth Science: The Physical Setting. Amsco School Pubns Inc. p. 571. ISBN 0-87720-196-X. Archived from the original (PDF) on 2008-06-25. Retrieved 2008-07-17.
  8. ^ "Making Sense of Nepal's Seti River Disaster". earthobservatory.nasa.gov. 24 January 2014.
  9. ^ "At least 105 dead as torrential rains inundate southern Russia". Los Angeles Times. 2012-07-07. Retrieved 2012-07-07.
  10. ^ Kuzmin, Andrey (2012-07-08). "Russia's Putin demands answers after floods leave 150 dead". msnbc.com. Reuters. Retrieved 2012-07-08.
  11. ^ "Uttarakhand: More than 5000 dead; 2000 still stranded". Business Standard. 2013-06-28. Retrieved 2013-06-28.
  12. ^ Jane, Sophie (2014-09-07). "Hundreds killed by landslides and flash floods triggered by heavy monsoon rains in Kashmir". Dailymail.co.uk. Retrieved 2014-12-04.
  13. ^ report, Advocate staff. "What caused the historic August 2016 flood, and what are the odds it could happen again?". The Advocate. Retrieved 2018-01-27.
  14. ^ "9 YOUTH DEAD IN SOUTHERN ISRAEL FLASH FLOODS". Retrieved 2018-04-26.
  15. ^ ecodellojonio.it (ed.). "Tragedia raganello: allerta gialla ignorata, tragedia evitabile" (in Italian). Retrieved 2018-08-21.
  16. ^ bbc.com (ed.). "Search for missing after 15 killed in Europe floods". Retrieved 2018-10-12.
  17. ^ "Wikipedia" (in French). Retrieved 2019-01-22.
  18. ^ http://www.jordantimes.com/news/local/death-toll-rises-21-dead-sea-flash-floods. Missing or empty |title= (help)
  19. ^ "Floodwaters deluge Iran, killing at least 23, after a month's worth of rain turns roads into rivers".
  20. ^ "Afghanistan Flooding Kills at Least 16, Official Says". AP via The Weather Channel. Retrieved 2019-03-29.

Further reading

External links

2015 Philmont Scout Ranch flash flood

On the morning of June 27, 2015, heavy rain occurred in a great portion of the Scouting reserve Philmont Scout Ranch, which is near Cimarron, New Mexico, United States, causing a flash flood. The flood also affected some other nearby areas in Colfax County that morning, including highways and small towns around Philmont. One youth Scout, Alden Brock, who was situated in a campsite within the staff camp Indian Writings, drowned while being swept away by the flood and died. The flood also had a significant impact on many individual crews and treks and significantly damaged some campsites. The 2015 flash flood is the largest documented flood in the history of Philmont, and is the only flood at Philmont that has ever caused the death of a person.

A Flash Flood of Colour

A Flash Flood of Colour is the third studio album by English rock band Enter Shikari, and was produced by Dan Weller. The album was recorded in May and June 2011 at Karma Sound Studios in Bang Saray, Thailand, and at the Fortress in London, United Kingdom. It was released internationally on 16 January 2012 by Ambush Reality, the band's record label in the United Kingdom, and Hopeless Records in North America.

Lyrically, the album deals with current affairs (primarily the Great Recession). It confronts flaws in government action to end the global recession, also touching on the political situation in Israel and climate change. A Flash Flood of Colour demonstrated Enter Shikari's continued fusion of electronic and rock music influences. The album's cover depicts an inverted social hierarchy.

A Flash Flood of Colour received generally positive reviews from music critics and an average Metacritic score of 75 out of 100. It debuted at number four on the UK Albums Chart after a band-led campaign to get the album to number one, and appeared on several album-of-the-year lists. To promote the album, Enter Shikari made A Flash Flood of Colour World Tour.

A Flash Flood of Colour World Tour

A Flash Flood of Colour World Tour was a concert tour by rock band Enter Shikari, which took place through 2012 and 2013, in support of the band's third studio album A Flash Flood of Colour, released on 16 January 2012. The tour supersedes the world tour that the band embarked on to support Common Dreads throughout 2009 and 2010. A Flash Flood of Colour was recorded in Bangkok, Thailand, between 8 May–14 June 2011.

Antelope Canyon

Antelope Canyon is a slot canyon in the American Southwest, on Navajo land east of Page, Arizona. It includes two separate, scenic slot canyon sections, referred to as Upper Antelope Canyon (or The Crack), and Lower Antelope Canyon (or The Corkscrew).The Navajo name for Upper Antelope Canyon is Tsé bighánílíní, which means 'the place where water runs through rocks'. Lower Antelope Canyon is Hazdistazí (called "Hasdestwazi" by the Navajo Parks and Recreation Department), or 'spiral rock arches'. Both are in the LeChee Chapter of the Navajo Nation. They are accessible by guided tour only.

Araluen, New South Wales

Araluen is a small town near Braidwood in the Southern Tablelands of New South Wales, Australia, in Queanbeyan-Palerang Regional Council. It lies in the valley of Araluen Creek, that joins the Deua River at roughly the midpoint in its course. At the 2016 census, Araluen had a population of 168 people.The name 'Araluen' meant 'water lily' or 'place of the water lilies' in the local Aboriginal language. At the time of European settlement Araluen was described as a broad alluvial valley with many natural billabongs covered with water lilies. Unfortunately, no such billabongs exist in the Araluen valley today. As with most river and creek valleys in south-eastern Australia, the natural landscape of Araluen Creek and its valley were destroyed by rampant and extremely destructive gold mining during the 'gold rush' in the latter half of the 19th century. The town experienced a decline after a flash flood in 1860 virtually destroyed the town, killing 24 people.

A second flash flood came in March, 2012 killing one person.Araluen experienced a great population increase during the gold rush. It had various schools between 1867 and 1956. Araluen West Public School operated from 1867 to 1919, although it was called Bourketown Public School during its first two years. Araluen Upper Public School operated from 1872 to 1888. Araluen Lower Provisional School operated from 1943 to 1956. Araluen West Evening Public School operated from 1880 to 1886 and in 1890 and 1892. Araluen Evening Public School operated in 1880 and 1881.The town was connected by road to Braidwood from its earliest days. Those travelling from the coast went via Braidwood, either over the Clyde Road (from Nelligen on the Clyde River) or the Braidwood Road (from Nowra). In 1867-1868, a road - Araluen Road - was built from Araluen to the coastal river town of Moruya.Two rare plants growing in the area are the Araluen Gum and the Araluen Zieria.

Brlog, Krško

Brlog (pronounced [bəɾˈlɔk]) is a small settlement in the Gorjanci Hills in the Municipality of Krško in eastern Slovenia. The area was traditionally part of Lower Carniola. It is now included in the Lower Sava Statistical Region.In 1973 a flash flood uncovered the entrance to Levak Cave (Slovene: Levakova jama). Speleologists found a human skull and other small artefacts. In 1975 the cave was excavated to reveal prehistoric Bronze Age and Roman occupation levels.


Coverack (Cornish: Porthkovrek, meaning cove of the stream) is a coastal village and fishing port in Cornwall, UK. It lies in the parish of St Keverne, on the east side of the Lizard peninsula about nine miles (14 km) south of Falmouth.Coverack has several hotels and a youth hostel. The area is a centre for watersports, particularly wind surfing, sailing and diving. The nearby rocks known as the Manacles have been the site of many shipwrecks and as a consequence are now a favourite diving destination.

Egma Sinkhole

EGMA Sinkhole (Turkish: EGMA Düdeni), a.k.a. Peynirlikönü Sinkhole, is a sinkhole and the deepest cave in Turkey. It is located at Sugözü village of Anamur, Mersin. The sinkhole is 1,429 m (4,688 ft) deep and 3,118 m (10,230 ft) long. EGMA stands for Evren Günay - Mehmet Ali Özel Sinkhole.

Beginning in 1993, the cave was being explored by BÜMAK (Boğaziçi University Speleological Society). A flash flood caused Mehmet Ali Özel to lose his life inside the cave in 2001. In 2004, with the help of members of the Bulgarian Speleological Federation, the BÜMAK team recovered Mehmet Ali's body and also reached the deepest point of the cave.

Enter Shikari

Enter Shikari is an English rock band formed in St Albans, Hertfordshire, England in 1999 under the name Hybryd by bassist Chris Batten, lead vocalist and keyboardist Roughton "Rou" Reynolds, and drummer Rob Rolfe. In 2003, guitarist Liam "Rory" Clewlow joined the band to complete its current lineup, and it adopted its current name. In 2006, they performed to a growing fanbase at Download Festival as well as a sold-out concert at the London Astoria. Their debut studio album, Take to the Skies, was released in 2007 and reached number 4 in the Official UK Album Chart, and has since been certified gold in the UK. Their second, Common Dreads, was released in 2009 and debuted on the UK Albums Chart at number 16; while their third, A Flash Flood of Colour, was released in 2012 and debuted on the chart at number 4. Both have since been certified silver in the UK. The band spent a considerable amount of time supporting the latter release through the A Flash Flood of Colour World Tour, before beginning work on a fourth studio album, The Mindsweep, which was released in 2015. Their fifth studio album The Spark was released in 2017.

Enter Shikari have their own record label, Ambush Reality. However, they have also signed distribution deals with several major labels to help with worldwide distribution. Their eclectic musical style combines influences from rock music genres with those from various electronic music genres, and they are considered key pioneers of electronicore.

Flash flood guidance system

The flash flood guidance system (FFGS) was designed and developed by the Hydrologic Research Center a non-profit public-benefit corporation located in of San Diego, CA, US, for use by meteorological and hydrologic forecasters throughout the world. The primary purpose of the FFGS is to provide operational forecasters and disaster management agencies with real-time informational guidance products pertaining to the threat of small-scale flash flooding throughout a specified region (e.g., country or portion of a country, several countries combined). The FFGS provides the necessary products to support the development of warnings for flash floods from rainfall events through the use of remote-sensed precipitation (e.g., radar and satellite-based rainfall estimates) and hydrologic models.

The FFGS outputs are made available to users to support their analysis of weather-related events that can initiate flash floods (e.g., heavy rainfall, rainfall on saturated soils) and then to make a rapid evaluation of the potential for a flash flood at a location. To assess the threat of a local flash flood, the FFGS is designed to allow product adjustments based on the forecaster's experience with local conditions, incorporation of other information (e.g., numerical weather prediction output) and any last minute local observations (e.g., non-traditional rain gauge data) or local observer reports. The system supports evaluations of the threat of flash flooding over hourly to six-hourly time scales for stream basins that range in size from 25 to 200 km2 in size.

Important technical elements of the flash flood guidance system are the development and use of a bias-corrected radar and/or satellite precipitation estimate field and the use of land-surface hydrologic modeling. The system then provides information on rainfall and hydrologic response, the two important factors in determining the potential for a flash flood. The system is based on the concept of flash flood guidance and flash flood threat. Both indices provide the user with the information needed to evaluate the potential for a flash flood, including assessing the uncertainty associated with the data.

Flash Flood Guidance is the amount of rainfall of a given duration over a small stream basin needed to create minor flooding (bankfull) conditions at the outlet of the stream basin. For flash flood occurrence, durations up to six hours are evaluated and the stream basin areas are of such a size to allow reasonably accurate precipitation estimates from remotely sensed data and in-situ data. Flash flood guidance then is an index that indicates how much rainfall is needed to overcome soil and channel storage capacities and to cause minimal flooding in a basin.

Flash Flood Threat is the amount of rainfall of a given duration in excess of the corresponding Flash Flood Guidance value. The flash flood threat when used with existing or forecast rainfall then is an index that provides an indication of areas where flooding is imminent or occurring and where immediate action is or will be shortly needed.

Flash flood warning

A Flash Flood Warning (SAME code: FFW) is issued by the United States National Weather Service when a flash flood is imminent or occurring in the warned area. A flash flood is a sudden, violent flood after a heavy rain, or occasionally after a dam break. Rainfall intensity and duration, topography, soil conditions, and ground cover contribute to flash flooding.

Most flash floods occur when there is a heavy amount of precipitation falling in an area and that water is then channeled through streams or narrow gullies. Flash floods may take minutes or hours to develop. It is possible to experience a flash flood without witnessing any rain.

Flash flood watch

A flash flood watch (SAME code: FFA; also referred as a "green box" by meteorologists) is issued by the National Weather Service when conditions are favorable for flash flooding in flood-prone areas, usually when grounds are already saturated from recent rains, or when upcoming rains will have the potential to cause a flash flood. These watches are also occasionally issued when a dam may break in the near future.Countries such as Australia also issue similarly worded warnings.

Flood alert

Flood alerts are issued by weather agencies to alert residents that flood conditions are a possibility.

Orting, Washington

Orting is a city in Pierce County, Washington, United States. The population as of the 2010 census is 7,983, according to the City of Orting.

Particularly Dangerous Situation

A Particularly Dangerous Situation (PDS) is a type of enhanced wording first used by the Storm Prediction Center (SPC), a national guidance center of the United States National Weather Service, for tornado watches and eventually expanded to use for other severe weather watches and warnings by local NWS forecast offices. It is issued at the discretion of the forecaster composing the watch or warning and implies that there is an enhanced risk of very severe and life-threatening weather, usually a major tornado outbreak or (much less often) a long-lived, extreme derecho event, but possibly another weather hazard such as an exceptional flash flood or fire.PDS watches are quite uncommon; less than 3% of watches issued by the SPC from 1996 to 2005 were PDS watches, or an average of 24 each year. When a PDS watch is issued, there are often more PDS watches issued for the same weather system, even on the same day during major outbreaks, so the number of days per year that a PDS watch is issued is significantly lower.

Philmont Scout Ranch

Philmont Scout Ranch is a ranch located near the town of Cimarron, New Mexico; it covers 140,177 acres (219 sq mi; 567 km²) of wilderness in the Sangre de Cristo Mountains of the Rocky Mountains. Donated by oil baron Waite Phillips, the ranch is owned and operated by the Boy Scouts of America. It is a National High Adventure Base where crews of Scouts and Venturers take part in backpacking treks and other outdoor activities. By land area, it is one of the largest youth camps in the world. During the season, between June 8 and August 22, an estimated 22,000 Scouts and adult leaders backpack through the Ranch's extensive backcountry. More than 1,130 seasonal staff are responsible for the Ranch's summer operations.

Philmont is also home to the Philmont Training Center and the National Scouting Museum and Seton Memorial Library. The Training Center is the primary location for BSA's national volunteer training programs. Philmont is a working ranch, maintaining small herds of cattle, horses, burros, and bison.

The only documented Tyrannosaurus rex track in the world was discovered within the camp's boundaries in 1993 in North Ponil Canyon by the Anasazi Trail Camp. It was formally identified in 1994.There are three other high adventure camps that the BSA owns and maintains: the Northern Tier National High Adventure Bases in Minnesota, as well as Manitoba and Ontario in Canada, Florida National High Adventure Sea Base in the Keys, and Summit Bechtel Family National Scout Reserve in southern West Virginia.


"Sssnakepit" is a single by English rock band Enter Shikari, the first from their third studio album "A Flash Flood of Colour". The single was released on 20 September 2011 as a digital download. The song charted at number 62 in the UK Singles Chart, number 11 on the UK Indie Chart and number 1 on the UK Rock Chart.


Tupiza is a city in Potosí Department, Bolivia. It is located at an elevation of about 2850 m. The population is 25,709 (2012 estimate). Tupiza and its environs are characterized by dramatic red escarpments which jut ruggedly skyward from the coarse, gray terrain; green agricultural land adjacent to the Tupiza River provides welcome respite from the otherwise arid, thorny surroundings. The area quebradas are susceptible to flash flood runoff from sudden cloudbursts.

Tupiza is the capital of the Sud Chichas Province within the Potosí Department. It is accessible via bus from Villazón to the south (and thereby both Argentina and Tarija) and Potosí to the north, as well as via the north-south train which served the mining settlements and runs the same route. From Tupiza, various towns in the local mining districts are accessible, as is the Salar de Uyuni.

Legend has it that Butch Cassidy and the Sundance Kid met their end at the hands of the Bolivian army near Tupiza, concluding their notorious string of bank robbery raids. Various local outfitters provide horseback or jeep tours to the rumored site.

Washout (erosion)

A washout is the sudden erosion of soft soil or other support surfaces by a gush of water, usually occurring during a heavy downpour of rain (a flash flood) or other stream flooding. These downpours may occur locally in a thunderstorm or over a large area, such as following the landfall of a tropical cyclone. If a washout occurs in a crater-like formation, it is called a sinkhole, and it usually involves a leaking or broken water main or sewerage pipes. Other types of sinkholes, such as collapsed caves, are not washouts.

Widespread washouts can occur in mountainous areas after heavy rains, even in normally dry ravines. A severe washout can become a landslide, or cause a dam break in an earthen dam. Like other forms of erosion, most washouts can be prevented by vegetation whose roots hold the soil and/or slow the flow of surface and underground water. Deforestation increases the risk of washouts. Retaining walls and culverts may be used to try to prevent washouts, although particularly severe washouts may even destroy these if they are not large or strong enough.



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