Unusual cause of wind damage in Upper Arlington and Hilliard
COLUMBUS, Ohio (WCMH) -- A few bands of showers and gusty thunderstorms rolled across the Columbus area early late Saturday afternoon and early evening, bringing much-needed rain after two weeks of dry weather.
However, the second line that formed a little after 6 p.m. caused pockets of straight-line wind damage in Upper Arlington and Hilliard associated with a "wet microburst."
As is often the case in a dry spell worsened by summer heat, the sporadic rain comes with some extra wind.
There was enough humidity to foment scattered storms ahead of a "backdoor cold front" dropping southwest across central Ohio, which is the opposite of a typical west-to-east frontal passage. The weird pattern is due to the alignment of the winds aloft flowing counterclockwise around low pressure over New England.
Very dry air associated with a broad area of upper-level high pressure often becomes entwined in a narrow cluster of storms, causing the raindrops to evaporate.
Evaporative cooling makes the air much heavier than the surrounding storm environment, creating powerful downdrafts that hit the ground with considerable force, often snapping branches, and sometimes felling trees that can become entangled with power lines in wooded areas.
As these pulse-type storms collapse, usually within an hour after forming, rain-cooled outflow acts as an exhaust mechanism, which can produce a concentrated surge of wind capable of reaching speeds of 50-80 mph in a very localized area.
The unusual trajectory of storms arriving from the northeast moving across the Scioto River Saturday may have also played a role in the more intense bursts of wind funneled through the smoother corridor of the river valley.
There was a narrow swath of pea-sized hail that preceded the strongest winds as the line moved west across Upper Arlington.
Multiple microburst events occur every year in Ohio, causing damage that spreads out in a straight line, rather than a rotary pattern associated with a tornado.