Sep 1, 2011
A record rain event in May in eastern Montana combined with high water from other storms in April and May, plus snow melt from a much above normal snow pack, to bring record high water to the Missouri River chain of reservoirs by late Spring. Then residual snow melt and additional rains caused record 13.8 million and 10.0 million acre feet of runoff above Sioux City during June and July respectively. All of this helped contribute and sustain record releases from the Missouri River Reservoirs fr
Source: NOAA National Weather Service Storm Events Database (event 335565). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Cass County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.