Tuesday, July 19, 2016

A Hard Rain



Watch this incredible microburst come crashing down over Phoenix

The Washington Post by Angela Fritz July 19 at 3:10 PM 

Check out this incredible video HERE 


As thunderstorms roiled across the Phoenix landscape on Monday night, this incredible microburst came crashing down from the sky in a blast of rain, hail and wind.


Jerry Ferguson, a helicopter reporter, took this incredible photo of the microburst during his flight.

Thunderstorm unleashes a microburst over Phoenix on Monday. (Bruce Haffner/Andrew Park/Jerry Ferguson

Thunderstorm unleashes a microburst over Phoenix on Monday. (Bruce Haffner/Andrew Park/Jerry Ferguson


Microbursts are small but powerful bursts of wind that rush downward out of a thunderstorm. When the microburst hits the ground, the damaging wind spreads out in all directions.


They form within the main downdraft of the storm, and are triggered by two main physical processes — the drag that’s created by falling rain and hail, and evaporation. When water evaporates it cools the air, which makes it more dense and accelerates the descent.



Once they reach the ground, microbursts have been known to produce wind gusts up to 150 mph.


Microburst diagram. (National Weather Service)

Angela Fritz is an atmospheric scientist and The Post's deputy weather editor.

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