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 downdraft that hits the ground and spreads horizontally with a burst of wind. 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.
A microburst produces straight-line winds. 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. The difference between a microburst and a tornado is that the wind from a microburst is pushed out of the storm. Wind from a tornado flows into the storm. The time duration for a microburst is about 5-15 minutes.
Areas affected by microbursts are 2.5 miles (4 km) or less. If the area affected is larger, 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. Ships can be damaged too if a microburst happens over water.
Microbursts are a major cause for airline accidents. An airplane affected by a microburst may have a loss in airspeed, loss of altitude, and major acceleration toward the ground. On August 2, 1985, a tragic plane accident occurred when a plane encountered a microburst at the Dallas-Ft. Worth Airport in Texas. This microburst had a wind speed of 80 mph (129 kph). Airports currently use Doppler radar and LLWSAS (Low Level Wind Shear Alert System) to spot microbursts and wind shears associated with microbursts. A wind shear is a sudden change in the wind speed and direction.
Shop Windows to the Universe Science Store!Cool It!
is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store
You might also be interested in:
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 things...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 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
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
An anemometer is a weather instrument used to measure the wind (it can also be called a wind gauge). Anemometers can measure wind speed, wind direction, and other information like the largest gust of wind...more