A powerful downdraft that spreads out in damaging straight-line winds upon reaching the surface, the broader category of storm wind event that includes the smaller, more concentrated microburst and its larger counterpart, the macroburst. Downbursts are a leading cause of what is sometimes mistaken for tornado damage, distinguished by the outward, fan-like pattern of fallen trees rather than a tornado's converging, twisted pattern.
Facts
PeriodicityIn the United States, straight-line wind events including downbursts are most common during the spring, when atmospheric instability is highest and weather fronts routinely cross the country. 1 ScaleMost downbursts are less than 4 km (2.5 miles) in extent and are called microbursts, while those larger than that are sometimes called macrobursts; downbursts may last from seconds to minutes and can produce straight-line winds of over 240 km/h (150 mph). 1 First DescribedThe term downburst was coined by mesoscale meteorologist Ted Fujita after he investigated the June 24, 1975 crash of an Eastern Air Lines flight in a thunderstorm at John F. Kennedy International Airport, concluding that a much smaller, more intense downdraft than a tornado had been at work. 2 Identification
Distinguishing AppearanceA downburst is a strong downward and outward gushing wind system that emanates from a point source above and blows radially in straight lines in all directions from the area of impact at the surface, so its damage radiates from a central point rather than the convergent, rotating pattern of a tornado. 1 Connections
Associated With
A derecho is defined as a widespread, long-lived windstorm produced by a family of downburst-producing thunderstorm clusters; the downbursts are the derecho's own constituent wind-damage mechanism.
Demonstrated By
Source National Oceanic and Atmospheric Administration
Sources
1. Downburst (Wikipedia)
Wikimedia FoundationDefinition section
Downbursts may be seconds to minutes long.
Seasonal occurrence passage
In the United States, such straight-line wind events are most common during the spring when instability is highest and weather fronts routinely cross the country.
View the Source 2. How Ted Fujita Revolutionized Tornado Science (Weather.com)
The Weather Company, 20201975 Eastern Airlines investigation passageQuote, 1975 Eastern Airlines investigation passage
On June 24, 1975, an Eastern Airlines flight crashed in a thunderstorm at John F. Kennedy International Airport in New York, killing 113 of the 124 people aboard. Fujita was asked to investigate the accident.
National Oceanic and Atmospheric Administration
National Oceanic and Atmospheric AdministrationDemonstrated By: GrasslandView the Source Reader Challenges (0)
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