September 2, 2014

Rare “Derecho” left mark on Iowa Monday

There’s a name for the storm that blew through Iowa early Monday: derecho. National Weather Service Meteorologist Jeff Johnson says it comes from a Spanish word for straight or direct.

“What it means, in meteorology terms, is a long-lived, intense wind event that usually stretches for several hundred miles in a west to east direction,” Johnson said. The derecho started around 3:20 Monday morning just north of Des Moines and ended around 18 hours later somewhere in the Atlantic Ocean. In Iowa, wind speeds topped out at 130 miles per hour around Vinton and Garrison.

“To put that in perspective, 130 mile per hour winds are equivalent to an EF2 tornado. So, that’s high end,” Johnson said. The winds ripped roofs off homes, toppled trees and power lines and flattened sections of corn fields across the state. There have been no reports of injuries. Some of the worst damage occurred in Tama County.

Johnson says the derecho was about five miles wide in Tama County with wind speeds of 80 to 105 miles per hour. This morning, Alliant Energy reported crews are still working to restore power to more than 14,000 customers. Rural Electric Cooperatives still had 3,300 customers without power today.

Several thousand MidAmerican Energy customers had their service restored by this morning. Johnson says, fortunately, derechoes are somewhat rare. “The last big one I can remember was back in 1998, a June 29th event,” Johnson said. “It formed in central Iowa and moved in a similar path just south of this one.”