DAMAGING DOWNBURSTS... A COMMON DANGER IN THE SOUTHWEST
Unlike tornadoes, damaging thunderstorm winds are relatively common across southwestern New Mexico and far western Texas. Under certain atmospheric conditions, thunderstorms and even rain showers will produce strong straight-line winds known as DOWNBURSTS. And within downbursts there may be concentrated swaths of destructive winds called MICROBURSTS. The winds within a microburst may blow in excess of 100 mph, potentially making them as destructive as a tornado.  What is usually required for a downburst or microburst is an environment which  includes a moist unstable air mass either above or below another layer of much drier air. When thunderstorms	In July, 2001, a strong thunderstorm downburst blew the roof  off  this  building in Tularosa, N.M. (Photographed by Ellis Neel Alamogordo Daily News)
or even rain showers develop and the attendant rain falls through the dry air, it evaporates, causing the air to cool and become much heavier than the surrounding atmosphere. This heavier air sinks rapidly to the ground where upon impact, it spreads outward causing an  onrush of strong and sometimes damaging winds at the surface.   In situations where the moist unstable air is aloft and the dry air is near the surface, a dry microburst may ensue, and the strong winds will occur possibly with some thunder but with little or no rainfall. In contrast, a wet microburst is more likely if the moist air covers the lowest levels beneath dry air aloft. During wet microbursts, damaging winds may be accompanied by heavy rains and even flash floods.  return to page 1	A strong microburst destroyed this small building in Chaparral, N.M. in August, 1988. page 9                         continued on page 10