text: in a storm what is a downburst?   thunderstorms have updrafts and downdrafts.  a downdraft is the area of sinking air.  a downburst a very strong downdraft where strong winds burst down toward the ground and spread out on the ground, producing damaging straight line winds. a downburst smaller than 2.5 miles in diameter is called a microbust.   downbursts are either wet (accompanied by precipitation) or dry (no precipitation, or virga).