NOAA’s 2011 National Spring Flood Outlook

Spring Flooding Underway, Expected to Worsen through April

A large swath of the country is at risk of moderate to major flooding this spring, from northeastern Montana through western Wisconsin following the Mississippi River south to St. Louis.

The highest spring flood risk areas include the Red River of the North, which forms the state line between eastern North Dakota and northwest Minnesota, the Milk River in eastern Montana, the James and Big Sioux Rivers in South Dakota, the Minnesota River, the upper Mississippi River basin from Minneapolis southward to St. Louis, and a portion of lower New York, eastern Pennsylvania and northern New Jersey. Many metropolitan areas have a greater than 95 percent chance of major flooding, including Fargo, Grand Forks, St. Paul, Davenport, Rock Island, Sioux Falls and Huron. Devils Lake in North Dakota has an 80 percent chance of reaching two feet above last year’s record of 1452.1 feet.

“For the third consecutive year, the stage is set for potential widespread, record flooding in the North Central United States,” said Jack Hayes, Ph.D., director of NOAA’s National Weather Service. “We’ve been coordinating with federal and state partners and high risk communities since December to raise awareness and help them prepare. All the ingredients are in place for major flooding so this situation should be taken very seriously. We’re asking citizens to stay informed and be prepared.”

The release of this outlook coincides with the annual Flood Safety Awareness Week campaign (March 14-19). NWS Weather Forecast Offices and River Forecast Centers across the Nation have teamed with the Federal Emergency Management Agency (FEMA) and others to raise public awareness about the dangers of flooding.

Causes for Spring Flooding

Spring flooding is caused by a variety of factors, including heavy late summer and fall precipitation, which leaves soils saturated and streams running high before the winter freeze; heavy winter snowfall resulting in deep snowpack; stable below-freezing temperatures throughout the winter delaying snow melt; frozen and/or saturated ground which inhibits infiltration of water into the soil, rapid snowpack melt due to warming springtime temperatures; backwater flooding due to ice jams; and heavy spring rainfall accelerating snow melt and adding to the high volume of water already in river systems. The rate at which temperatures warm this spring, along with the impacts of any additional precipitation, will determine the magnitude, timing and extent of the flooding.

National Weather Service models show this year’s snowpack in the north-central U.S. contains a water content ranked among the highest of the last 60 years

Each year floods kill more than 100 people and are responsible for approximately $7 billion in damage. Extensive and persistent public education on the hazards of flooding is key to reducing loss of life and property.

Further Information on the Web:

Spring Flood Outlook:

Temperature and Precipitation Long Range Forecast:

Drought Outlook:

FEMA and NOAA’s National Weather Service provide tips and information to help individuals and families prepare for flooding dangers and these resources can be accessed online at the Flood Safety Awareness page.

Individuals can also learn more about seasonal flood risks and what to do to prepare by visiting FEMA’s FloodSmart website, or by calling 1-800-427-2419.