National Weather Service United States Department of Commerce


A fairly localized cluster of thunderstorms developed over northeast Iowa and southwest Wisconsin Monday evening, July 11th 2017. The storms developed rapidly, becoming strong to severe. Large hail and damaging winds accompanied a few of the storms early, but the main threat quickly moved to heavy rainfall and flash flooding.

Flash flooding occurred across parts of southeast Clayton county Iowa and into Grant county Wisconsin where over 5-8 inches of rain was measured in local rain gages. Social media reports of 4" of rain in one hour were seen, but not confirmed. Voluntary evacuations occurred along the Turkey River and Mill Creek south of Osterdock IA. Washouts occurred on many driveways and roads in both counties, with mudslides also reported in Grant county Wisconsin. 

Some of the higher rainfall totals:

4 miles west of North Buena Vista, Iowa 8.25"
Osterdock, Iowa 8.20"
Guttenberg, Iowa 5.57"
Garber, Iowa 5.39"


12 hour rainfall radar estimates, ending 7 am July 12, 2017