Thunderstorm Wind in Woodbury County, Iowa

Thunderstorm winds caused widespread damage in and near Sioux City. Tree damage included large trees blown down, blocking several roads. A few vehicles were destroyed and numerous vehicles damaged by falling trees and tree debris. Falling trees also damaged several residences and garages, causing one known injury. The winds lifted a three car garage off its foundation, and overturned it onto a nearby pasture. One large tree split an occupied trailer in the middle, missing residents who were sleeping at both ends. Numerous power lines and poles were blown down or broken, leaving an estimated 19,000 customers without power, several thousand of which were still without power 24 hours later. Numerous buildings, especially residences, sustained roof damage, especially to shingles. The winds damaged or blew down several signs, damaged fences, and blew down a large awning that sheltered gasoline pumps at a convenience store. The winds flattened crops near the city, but the amount of crop damage was not known, especially since crops were expected to partially recover.

Thunderstorms produced damaging winds in a few locations in northwest Iowa from a little before to just after midnight on the night of July 20th and 21st. The greatest damage was in and near Sioux City.