Downburst winds are created by an area of significantly rain-cooled air that, after hitting ground level, spreads out in all directions, producing strong winds. Unlike winds in a tornado, winds in a downburst are directed outward from the point where they hit land or water.
Dry downbursts are associated with thunderstorms that contain very little rain, while wet downbursts are created by thunderstorms with high amounts of rainfall.
On most days, thunderstorm activity will end between midnight and 1 a.m. As these thunderstorms die down, this is the most common time for a downburst to occur, resulting in severe wind gusts that can cause extensive damage.
Downbursts create vertical wind shears or microbursts, which are dangerous to aircrafts.
Microburst and downburst winds are gusts of wind that have the potential to be as strong as hurricane force winds. They are made up of a column of sinking air that is capable of producing straight-line winds of over 150 mph.
Straight-line winds are very strong winds that produce damage, demonstrating the lack of a rotational damage pattern. Such rotational damage patterns are associated with cyclonic storms, including tornadoes and tropical cyclones. Straight-line winds are common with the gust front of a thunderstorm and can also originate with a downburst from a thunderstorm.
They don’t happen very often, but they do happen fast. Telephone poles, trees and other objects can be knocked over instantly.
On August 14, 1996, a wind gust of 115 mph was recorded at the Deer Valley Airport and the resulting damage exceeded $160 million.
