A gust front is a strong gust
released by a thunderstorm
as it reaches maturity
. Gust fronts are often evident by a wall of dust
(in dry areas) or rain, pushing out from a storm. They are often created by microbursts
, severe downdrafts
emerging from thunderstorm
s. As they move out, they may change from a swirling mass under the storm to a sometimes imposing wall of dust
. Gust fronts can be quite severe
; they may reach above hurricane
strength and much damage blamed on tornados
is actually caused by gust fronts.
I had the experience of witnessing one of these firsthand in the Mojave Desert near Death Valley. The day had been extremely hot - over 120 degrees - but to the east there was an impressive line of thunderstorms. The line did not look that different from other lines of storms common in the desert, but as the sun set it became evident that the storm was creating almost constant lightning. We watched from our campsite as the line crested ridge after ridge, hammering each with incessant lightning - we saw one peak hit at least 10 times. As the storm moved over the nearest ridge, and we began to feal uneasy, we noticed a whistling sound on the hill. It was crazy - one of the eeriest sounds I had ever heard. The temperature had stabilized at 108 and until this instant, the wind was calm. Suddenly, the whistling moved audibly down the hills and at that instant the wind hit so hard i was literally knocked off my feet. The gust front moved through in about 3 gusts and totally trashed our campsite, then was gone. The air was nearly still again but it had cooled off about 20 degrees.
At this point the thunderstorm was quite close, and since we were in a dry wash, we decided it would be a good time to get the hell out of there. Ironically, the storm seemed to die down a bit after we left - often (but not always!) a gust front is a symbol that a storm is on the decline.