AUSTIN (KXAN) — Tree limb damage and a destroyed billboard on North Lamar Boulevard Monday were the result of a weather phenomenon known as a “microburst,” and it was captured on video.
Downburst, or on a smaller scale, microburst winds are not rare in Texas thunderstorms, but capturing them in a video time lapse is. That is exactly what Victor Ituarte did while heavy thunderstorms moved over the middle of Austin late Monday afternoon.
His video captured the dramatic moment the collapsing pocket of cold air and rain rushed to the ground, fanning out at speeds of 40-50 mph.
Here is more information on microbursts from the National Weather Service:
What is a Microburst?
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.
What causes a Microburst?
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.
Wind speeds in microbursts can reach up to 100 mph, or even higher, which is equivalent to an EF-1 tornado! Winds this high can cause major damage to homes and other structures and level hundreds of trees. It is very important that you take Severe Thunderstorm Warnings just as seriously as Tornado Warnings!