IARN — Wind speeds from the August 10th derecho that swept through Iowa were stronger than initially surveyed, according to new data collected from the National Weather Service Quad Cities office.
In revised estimates released on Wednesday, the weather service said the maximum wind speeds were approximately 140 miles per hour in the southwest portion of Cedar Rapids. Those wind speeds are equivalent to a Category 4 hurricane or an EF-3 tornado. Other new estimates show straight-line winds were as high as 100-to-130 miles per hour in parts of Benton, Linn, Jones, Cedar, and Clinton counties.
Iowa state climatologist Justin Glisan recently said the derecho held together for a 770 mile stretch over 14 hours. He says the storm system lost its strength as it entered western Ohio.
“The August 10th derecho event formed in the early morning hours in southeastern South Dakota and moved into Nebraska as a pretty put-together line of thunderstorms,” Glisan said. “It crossed the border into Iowa at about 8 or 9 a.m. and some severe thunderstorm warnings were issued along that line. We weren’t necessarily sure that line would hold together. It wasn’t until it moved into central Iowa that we really started to see the thunderstorm complex strengthen and those wind speeds start to pick up. This was as the derecho was starting to consolidate.”
Other wind speeds from the storm reported to the National Weather Service were 106 miles per hour at a personal weather station two miles west northwest of Le Grand, 99 miles per hour at the Marshalltown Airport, and 90 miles per hour south of Chelsea.
The 140 mile per hour wind gusts in southwest Cedar Rapids reportedly caused damage to an apartment complex in that area by removing its roof, outside walls, and some inside walls from the top floor. The winds also destroyed or damaged numerous outbuildings, barns, grain bins, homes, mobile homes, trees, and power poles.
Story courtesy of the Iowa Agribusiness Radio Network.
