The National Weather Service says macrobursts downed large tree limbs and snapped some telephone poles along two stretches in the Baltimore area Wednesday. They estimated that wind speeds approached 90 mph.
What is a macroburst?
It’s a sustained pulse of severe straight-line winds caused by rapid downdraft of air within a tall storm cloud. The winds can reach speeds of more than 130 mph, last for five to 30 minutes, and extend across an area more than 2½ miles wide. (A microburst, on the other hand, involves winds approaching 170 mph over an area less than 2½ miles wide.)
To the casual observer, damage caused Wednesday in White Marsh and in the Baldwin and Fallston areas, along the border between Baltimore and Harford counties, appeared to be caused by a tornado.
And meteorologists said images of an ominous cloud in that area did not show a funnel cloud, but rather what appeared to be a roll cloud — a relatively rare tube-shaped cloud commonly mistaken for a tornado.