NationMaster - Encyclopedia: Derecho

A derecho is a widespread and long-lived, violent convectively induced windstorm that is associated with a fast-moving band of severe thunderstorms usually taking the form of a bow echo. Derechos are usually not associated with a cold front, but a stationary front. A warm weather phenomenon, they occur mostly in late spring to summer, especially July, but can occur at any time of the year. This article or section does not cite its references or sources. ... A derecho is a widespread and long-lived, violent convectively induced windstorm that is associated with a fast-moving band of severe thunderstorms usually taking the form of a bow echo. ... A guide to the symbols for weather fronts that may be found on a weather map: 1. ...

1 Word origin
2 Types of derechos
3 Who is at risk during derechos?
4 See also
5 External links and sources

Word origin

Derecho comes from a Spanish word for "direct" or "straight ahead". The word first came about in the American Meterological Journal in 1888 by Dr. Gustavus Hinrichs. In contrast, tornado comes from the Spanish word "tornar" meaning "to turn". 1888 (MDCCCLXXXVIII) is a leap year starting on Sunday (click on link for calendar) of the Gregorian calendar or a leap year starting on Tuesday of the Julian calendar. ... Union City, Oklahoma tornado (1973) A tornado is a violently spinning column of air in contact with both a cumiliform cloud base and the surface. ...

Derechos come from a band of thunderstorms that are bow- or spearhead-shaped, and hence are also called a bow echo or spearhead radar echo. The size of the bow may vary and the storms may die and redevelop. Winds in a derecho can be enhanced by downburst clusters embedded inside the storm. These straight-line winds can exceed 100 mph (160 km/h) in these clusters. Tornadoes sometimes form within derecho events, although such are often difficult to confirm due to the additional damage caused by straight-line winds. A downburst is a column of sinking air that is capable of producing damaging straight-line winds over 100 mph, similar to, but distinguishable from tornadoes. ...

Derechos form from May to August, mostly July. During this time of year, derechos are usually confined to the Ohio Valley, upper Mississippi Valley and the Great Lakes region including southern Canada, mostly in Southwestern Ontario. They often occur during a period of extreme heat along stationery fronts on the northern side of where the most intense heat is. Official language(s) None Capital Columbus Largest city Columbus (largest metropolitan area is Cleveland) Area - Total - Width - Length - % water - Latitude - Longitude Ranked 34th 116,096 kmÂ² 355 km 355 km 8. ... Official language(s) English Capital Jackson Largest city Jackson Area - Total - Width - Length - % water - Latitude - Longitude Ranked 32nd 46,914 kmÂ² 275 km 545 km 3 30Â°13N to 35Â°N 88Â°7W to 91Â°41W Population - Total (2000) - Density Ranked 31st 2,697,243 23. ... This article is about the group of North American lakes. ... Western Ontario is a region of Ontario centred on London, Ontario. ...

Late-year derechos are confined to Texas and the deep south, although a late-summer derecho struck upper New York State after midnight on September 7, 1998. Derechos have been known to occur in other parts of the world. One such event occurred on July 10, 2002 in Germany. A serial derecho killed eight people and injured 39 near Berlin. Official language(s) None. ... The New York State Labor Day Derechos were two derecho events that occurred on Labor Day, September 7, 1998. ... State nickname: Empire State Other U.S. States Capital Albany Largest city New York Governor George Pataki Official languages None Area 141,205 km² (27th) - Land 122,409 km² - Water 18,795 km² (13. ... September 7 is the 250th day of the year (251st in leap years). ... 1998 (MCMXCVIII) was a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ... July 10 is the 191st day (192nd in leap years) of the year in the Gregorian Calendar, with 174 days remaining. ... For the Cusco album, see 2002 (album). ... (helpÂ· info) is the capital city and a federal state of Germany. ...

Types of derechos

There are three types of derechos:

Serial derecho - Multiple bow echoes embedded in a massive squall line typically around 250 miles (400 km) long. This type of derecho is usually associated with a very deep low. One example of the serial type is a derecho that occurred during the Great Blizzard of 1993 in Florida. Also because of embedded supercells, tornadoes can easily spin out of these types of derechos.

Progressive derecho - A small line of thunderstorms take the bow-shape and can travel for hundreds of miles. An example of this is a derecho is one that moved through Minnesota, Wisconsin, Michigan, Ontario, Quebec and Maine on July 4 and July 5, 1999. This particular derecho is named the "Boundary Waters-Canadian Derecho"

Hybrid derecho - Has characteristics of a serial and progressive derecho. These types of derechos are associated with a deep low like serial derechos, but are relatively small in size like progressive derechos. An example is the one that moved through the central Northern Plains and the Southern Great Lakes on May 30, 1998.

According to the National Weather Service criterion, a derecho is classified as a band of storms that have winds of at least 50 knots (58 mph or 93 km/h) along the entire derecho. A low pressure area, or a low for short, is a region where the atmospheric pressure is lowest with relation to the surrounding area. ... The 1993 North American storm complex, also known as the 93 Superstorm or the [Great] Blizzard of 1993, was a large cyclonic storm that occurred on March 12- 14, 1993 on the East Coast of North America. ... Official language(s) English Capital Tallahassee Largest city Jacksonville Area - Total - Width - Length - % water - Latitude - Longitude Ranked 22nd 170 451 kmÂ² 260 km 800 km 17. ... Satellite view of a supercell A supercell is thunderstorm with a deep rotating updraft (a mesocyclone) [1]. Supercell thunderstorms are the largest, most severe class of single-cell thunderstorm. ... Union City, Oklahoma tornado (1973) A tornado is a violently spinning column of air in contact with both a cumiliform cloud base and the surface. ... Official language(s) None Capital Saint Paul Largest city Minneapolis Area - Total - Width - Length - % water - Latitude - Longitude Ranked 12th 225,365 kmÂ² 400 km 645 km 8. ... Official language(s) None Capital Madison Largest city Milwaukee Area - Total - Width - Length - % water - Latitude - Longitude Ranked 23rd 169,790 kmÂ² 420 km 500 km 17 42Â°30N to 47Â°3N 86Â°49W to 92Â°54W Population - Total (2000) - Density Ranked 18th 5,453,896 38. ... Official language(s) English de-facto Capital Lansing Largest city Detroit Area - Total - Width - Length - % water - Latitude - Longitude Ranked 11th 250,494 kmÂ² 385 km 790 km 41. ... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages English (French has some legal status) Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation - House seat - Senate seats 106 24 Area Total â€¢ Land â€¢ Water (% of total) Ranked... Motto: Je me souviens (French: I remember) Official languages French Capital Quebec City Largest city Montreal Lieutenant-Governor Lise Thibault Premier Jean Charest (PLQ) Parliamentary representation - House seat - Senate seats 75 24 Area Total â€¢ Land â€¢ Water (% of total) Ranked 1st 1,542,056 kmÂ² 1,183,128 kmÂ² 176,928... Official language(s) None Capital Augusta Largest city Portland Area - Total - Width - Length - % water - Latitude - Longitude Ranked 39th 86,542 kmÂ² 305 km 515 km 13. ... July 4 is the 185th day of the year (186th in leap years) in the Gregorian Calendar, with 180 days remaining. ... July 5 is the 186th day of the year (187th in leap years) in the Gregorian Calendar, with 179 days remaining. ... 1999 (MCMXCIX) was a common year starting on Friday, and was designated the International Year of Older Persons by the United Nations. ... The Boundary Waters-Canadian Derecho, also commonly called the Boundary Waters Blowdown, was an international derecho that occurred during the afternoon and evening hours of July 4 and the early morning hours of July 5, 1999. ... May 30 is the 150th day of the year in the Gregorian calendar (151st in leap years). ... 1998 (MCMXCVIII) was a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ... The National Weather Service (NWS) is one of the six scientific agencies that make up the National Oceanic and Atmospheric Administration (NOAA) of the United States government. ...

Who is at risk during derechos?

Since derechos occur during warm months, people who are most at risk are those involved in outdoor activities. Campers, hikers, and motorists are most at risk because of falling trees. Most casualties in derechos come from trees falling on cars.

People who live in mobile homes are also at risk. Mobile homes are not bolted to the ground, so they can be overturned from the high winds.

When a strong derecho hits a city, power outages caused by damaged powerlines may occur. The largest city to have been hit by more than one derecho is Grand Rapids, which has been hit by two such events (once on July 7, 1991 and again on May 30, 1998). Nickname: Furniture City Motto: Official website: http://www. ... July 7 is the 188th day of the year (189th in leap years) in the Gregorian Calendar, with 177 days remaining. ... 1991 (MCMXCI) was a common year starting on Tuesday of the Gregorian calendar. ... May 30 is the 150th day of the year in the Gregorian calendar (151st in leap years). ... 1998 (MCMXCVIII) was a common year starting on Thursday of the Gregorian calendar, and was designated the International Year of the Ocean. ...

External links and sources

Facts about derechos (Storm Prediction Center)
What is a derecho? (University of Nebraska at Lincoln)
What is a derecho? (Meteorologist Jeff Haby's education page)
Extreme Convective Windstorms: Current Understanding and Research (Report of the Proceedings (1994) of the U.S.-Spain Workshop on Natural Hazards (Barcelona, Spain, 8-11 June 1993), J. Corominas and K.P. Georgakakos, Eds., pp. 44-55)
Derecho Hazards in the United States (Walker Ashley)
Examination of Derecho Environments Using Proximity Soundings (Weather and Forecasting, Jeffry S. Evans, Charles A. Doswell III)
StormWiki

Categories: Derechos | Storms The Storm Prediction Center, located in Norman, Oklahoma, is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service, which in turn is part of the National Oceanic and Atmospheric Administration (NOAA) of the U.S. government. ... The University of Nebraskaâ€“Lincoln is a state-supported institution of higher learning located in Lincoln, Nebraska, USA. Often referred to as simply Nebraska or UNL, it is the flagship and largest campus of the University of Nebraska system. ... Weather and Forecasting is a publication of the American Meteorological Society. ...

Results from FactBites:

Facts About Derechos Which Are Very Damaging Windstorms (2343 words)
	Derechos are associated with a band of showers or thunderstorms that are often "curved" in shape.
	An example of serial derecho with a very extensive squall line and with embedded smaller scale bow echoes is the one that affected Florida, Cuba, and adjacent portions of the Gulf of Mexico, the Caribbean Sea, and the Atlantic Ocean on March 12-13, 1993.
	The second type of derecho is called a "progressive" derecho and it is associated with a relatively short line of thunderstorms (typically from 40 miles to 250 miles in length) which may at times take the shape of a single bow echo, particularly in the early stages of development.

Derecho - Academic Kids (578 words)
	A Derecho is a widespread and long-lived windstorm that is associated with a fast-moving band of severe thunderstorms.
	Derechos are usually not associated with a cold front, but a stationary front.
	Late-year derechos are confined to Texas and the deep south, although a late-summer derecho struck upper New York State after midnight on September 7, 1998.

More results at FactBites »

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Contents

Word origin GA_googleFillSlot("encyclopedia_square");

Types of derechos

Who is at risk during derechos?

See also

External links and sources

Word origin