Flash Flood in Olmsted County, Minnesota

The approach on the north side of the County Road 18 bridge going through Oronoco washed out as the Middle Fork of the Zumbro River flooded. The Lake Shady Dam was also damaged.

A stationary front set up across southern Minnesota on the evening of September 22nd. As an unusually moist air mass flowed over this boundary, heavy rain developed and fell repeatedly across the area during the evening and overnight hours. Soils were abnormally wet for this time of year, therefore the extreme rainfall amounts that fell caused widespread significant river flooding and flash flooding. Infrastructure was greatly affected with millions of dollars of damage, while private properties were also heavily damaged. Dodge, Olmsted, Wabasha, Winona, and Mower counties were included in federal disaster declarations (FEMA-1941-DR).