SPRINGFIELD, Mass (WWLP) — In early July, a thunderstorm microburst led to damage in the Longmeadow area that looked just like a tornado ripped through. While the damage is comparable to tornadoes, microbursts form very differently and are a threat with strong thunderstorms.
A microburst is a column of rapidly sinking air in a thunderstorm that hits a small area, usually less than 2.5 miles in diameter.
Updrafts, or columns of upward-moving air, are present in a strong thunderstorm, but dry air and other factors can cause that updraft to weaken.
Once an updraft weakens, it can no longer hold up the core of heavy rain and hail suspended high in the thunderstorm. Once the core collapses, it drops to the ground and spreads in all directions.
The worst of the damage occurs right where that air first hits the ground. It’s possible for these winds to reach over 100 miles per hour, which is equivalent to damage from an EF1 tornado. It’s this reason that severe thunderstorm warnings need to be taken just as seriously as tornado warnings, especially since microbursts are very hard to detect.
Since microbursts are short-lived, only happening for a few minutes, they can occur between different scans of the radar, which is another reason they can come with little or no warning at all.