February 18, 2011
North Central U.S. Spring Flood Risk Map as of Feb. 17, 2011.
Download here. (Credit: NOAA)
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, National Weather Service flood experts are forecasting. Today the agency released an initial spring flood outlook for this high risk region and will release a national spring flood outlook on March 17.
For the third consecutive year, forecasters predict moderate to major flooding along the Red River of the North, which forms the state line between eastern North Dakota and northwest Minnesota and includes the Souris River Basin and the Devils Lake and Stump Lake drainages in North Dakota.
If the current forecast holds, the main stem Mississippi River is at risk for moderate to major flooding from its headwaters in St. Paul, Minn., all the way to St. Louis.
Areas of greatest flood concern are:
Devils Lake, N.D.
Red River of the North in North Dakota and Minnesota
James River and the Big Sioux River in South Dakota
Upper Mississippi River in Minnesota, Wisconsin, Iowa, Illinois and Missouri
NOAA’s flood forecasters point to several reasons for the anticipated floods. The ground in much of the north-central United States is frozen, water-saturated, and snow-covered. Forecasts for much of the region continue to call for persistent below-normal temperatures and above-normal precipitation for February, with an expectation for the snow pack to grow. In March and April, as temperatures rise and the snow melts, frozen ground and saturated soil will enhance runoff, causing streams and rivers to swell. The timing and the rate of snow melt and any rain that falls during snow melt contribute to the magnitude and extent of flooding.
“Excessive precipitation, mainly in the form of snow, coupled with continuously frigid temperatures has yielded a thick snowpack in much of the upper Midwest. We expect significant flooding when this snow begins to melt,” said Lynn Maximuk, central region director of the National Weather Service. “We urge residents in risk areas to closely monitor NOAA’s river forecasts and warnings, and prepare now for flooding.”
For complete details, see the spring flood outlook at http://www.weather.gov/oh/hic/nho.
NOAA forecasters gauge flood risk by examining the impacts of precipitation, groundwater conditions, stream flow, snow conditions and weather forecasts. Computer models assist the forecaster by using these variables to calculate the probability that a certain river or lake will exceed its flood level (available online at http://water.weather.gov).
Aware of the likelihood North Central U.S. spring flooding months in advance, forecasters from National Weather Service field offices began coordinating with United States and Canadian agencies in December to get an early jump on flood mitigation efforts. Several federal, tribal, state and local partners on both sides of the border routinely coordinate to communicate flood potential, plan and prepare.
To help people and communities prepare, NOAA offers the following flood safety tips:
"FEMA, through our regions, is working closely with our state partners to ensure we are doing everything we can to support their efforts to prepare for this coming spring flood season, but we also must rely on a key partner in this team - the public," said Darryl J. Madden, director, Ready Campaign. "There are simple steps individuals and families can take now, to ensure their families are safe. By having a plan and preparing an emergency kit, individuals and families will be better prepared to respond to flooding - our nation's most common disaster. Anyone can visit http://www.ready.gov to learn more."
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