The top three pictures show a microburst in action. Dust and dirt caught in the air make the path of the wind visible. The bottom picture shows tree damage from the 70-90 mph (112-145kph) straight line winds of a microburst. This microburst was part of a severe thunderstorm that went through Lawrence, KS on March 12, 2006.
Courtesy of NOAA Photo Library, NOAA Central Library, National Weather Service Forecast Office of Topeka, KS/ KHP

Type of Wind: Microburst

Microbursts are dangerous winds that are created by thunderstorms. A microburst is a downward burst of wind, a downburst, that hits the ground and spreads horizontally. The strong downdraft causing the microburst is formed by cooling. The cooling is caused by evaporation in a cloud. Once the strong downdraft has formed, it is trying to push the cool air out of the cloud to create a balance with the warm temperatures of the surrounding air.

Microbursts are typically associated with severe thunderstorms but can also be part of smaller thunderstorms or clouds with isolated showers. Lightning and thunder are not essential for a microburst.

A microburst produces straight-line winds that last for five to 15 minutes. Straight-line winds are not associated with any type of rotation. These winds can be greater than 104 mph (167 kph) and as much as 168 mph (270 kph); the wind speeds can be equal to the winds of small tornadoes. There is a difference between a microburst and a tornado; the difference is that the wind in the microburst flows outward from the storm rather than into the storm like a tornado.

The area affected by a microburst is 2.5 miles (4 km) or less. If winds beneath a thunderstorm extend over a larger area, then it is called a macroburst. The damage from a microburst can look similar to that of a tornado. Damage from a microburst includes: blown down trees and heavy damage to poorly built structures and sailing vessels if the microburst occurred over open water.

Microbursts are the second leading cause of airline accidents. A microburst may cause an airplane to loose airspeed and altitude, and accelerate toward the ground. On August 2, 1985, a tragic plane accident occurred from a microburst at the Dallas-Ft. Worth Airport in Texas. The wind speed from this microburst was measured to be 80 mph (129 kph). Airports currently use Doppler radar and LLWSAS (Low Level Wind Shear Alert System) for spotting microbursts and wind shears associated with microbursts. A wind shear is a sudden change in the wind speed and direction.

Theodore Fujita first identified microbursts in 1975. It is thought that, prior to his identification, some damage that had been attributed to tornadoes was in fact caused by microbursts.

Last modified June 26, 2008 by Vanessa Pearce.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more


Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates different pressures in the atmosphere which creates the winds around the globe. Since the Earth spins,...more


Thunderstorms are one of the most thrilling and dangerous types of weather phenomena. Over 40,000 thunderstorms occur throughout the world each day. Thunderstorms form when very warm, moist air rises into...more


One process which transfers water from the ground back to the atmosphere is evaporation. Evaporation is when water passes from a liquid phase to a gas phase. Rates of evaporation of water depend on factors...more

Thunder and Lightning

Lightning is the most spectacular element of a thunderstorm. In fact it is how thunderstorms got their name. Wait a minute, what does thunder have to do with lightning? Well, lightning causes thunder....more


Rainbows appear in the sky when there is bright sunlight and rain. Sunlight is known as visible or white light and is actually a mixture of colors. Rainbows result from the refraction and reflection of...more

The Four Seasons

The Earth travels around the sun one full time per year. During this year, the seasons change depending on the amount of sunlight reaching the surface and the Earth's tilt as it revolves around the sun....more

Research Aircraft

Scientists sometimes travel in specially outfitted airplanes in order to gather data about atmospheric conditions. These research aircraft have special inlet ports that bring air from the outside into...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA