Thursday, July 21, 2016
A microburst is a localized column of sinking air (downdraft) within a thunderstorm and is usually less than or equal to 2.5 miles in diameter. Microbursts can cause extensive damage at the surface, and in some instances, can be life-threatening. There are two primary types of microbursts: 1) wet microbursts and 2) dry microbursts.
Wet microbursts are accompanied by significant precipitation and are common in the Southeast during the summer months.
It all starts with the development of a thunderstorm and the water droplets/hailstones being suspended within the updraft. Sometimes an updraft is so strong it suspends large amounts of these droplets and hailstones in the upper portions of the thunderstorm.
There are many factors that can lead to evaporational cooling (sinking air) and therefore weakening of the updraft. Once this occurs, it is no longer capable of holding the large core of rain/hail up in the thunderstorm. As a result, the core plummets to the ground. As it hits the ground it spreads out in all directions. The location in which the microburst first hits the ground experiences the highest winds and greatest damage.
Watch: Microburst Over Phoenix, Arizona - July 18th, 2016https://vimeo.com/175329108