Jul 1, 2011
A record rain event in May in eastern Montana combined with other storms in April and May plus early spring snow melt and brought record high water to the Missouri River chain of reservoirs. Heavy rain events and late season snow melt contributed to record runoffs above Sioux City in June of 13.8 million acre feet, and in July of 10 million acre feet. These all contributed to record releases from the Missouri River Reservoirs. Releases from Gavins Point Dam, which is the last in the chain, in
Source: NOAA National Weather Service Storm Events Database (event 309607). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Harrison County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.