This presentation will describe the conditions which produced record flooding in the Missouri River watershed during the spring and summer of 2011, the hydrologic response which required unprecedented releases from the Missouri River main stem reservoirs, and the damage caused by the flood. In addition, services provided by the National Weather Service during the flood will be presented.

Record breaking snowfall occurred at many locations in the upper part of the Missouri River basin during the winter and spring of 2011, leading to significant snowmelt flooding in April 2011. This was followed by record breaking rainfall on already saturated soil which led to a second round of flooding across much of eastern Montana in May and June.

The extreme runoff generated by the snowmelt and rainfall resulted in the U.S. Army Corps of Engineers releasing record amounts of water from their 6 main stem reservoirs on the Missouri River. In spite of extraordinary efforts by the Corps of Engineers and other federal agencies, state and local governments, and private citizens to minimize flood damage, the runoff and releases caused extensive damage to roadways, levees, farmland, and communities along the river.

The National Weather Service (NWS) Weather Forecast Offices and the Missouri Basin River Forecast Center issued thousands of river forecasts and flood warning products during this event. In addition, NWS personnel provided on-site meteorologic and hydrologic assistance to local and state emergency management offices across the basin and the Corps of Engineers' Joint Information Center in Omaha, Nebraska.