National Weather Service warns of widespread spring flooding<
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WASHINGTON, March 24 - With spring flooding already underway over portions of the U.S., NOAA forecasters are warning the worst is yet to come. Almost half the country - from the North Central U.S. through the Midwest and the Northeast - has an above-average risk of flooding over the next few weeks, according to the annual spring outlook released by NOAA's National Weather Service (NWS).
Map Source: NOAA, National Weather Service, National Hydrologic Assessment
Davenport, Iowa is taking the flood warning seriously. With volunteers filling sandbags and city workers' vacation requests postponed until the flood threat ends in early April, Davenport is testing pumps, raising earth berms and preparing for what could be the city's worst flood since 1993.
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% chance of major flooding, including Davenport, Fargo, Grand Forks, St. Paul, Rock Island, Sioux Falls and Huron. Devils Lake in North Dakota has an 80% 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.”
Warm temperatures in the forecast could cause much of the snowpack to melt across South Dakota and southern Minnesota, setting off moderate to major flooding in eastern South Dakota next week. Minor flooding could begin now on the Mississippi River and its tributaries over southeastern Minnesota and southwestern Wisconsin, leading to moderate to major flooding by early April.
In addition, a series of storm systems are forecast to move across the region during the next two weeks, which could bring additional snow or rain on top of the remaining snowpack. These systems may cause substantial runoff and the beginning of minor flooding in the southern headwater portion of the Red River of the North, eventually leading to major flooding sometime from the last week of March through early April.
The NWS report notes that 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.
Other aspects of the U.S. spring outlook for April through June include:
Temperature: Odds favor above-average temperatures in much of the southern half of the U.S., and below-average temperatures from the Pacific Northwest to the northern plains.
Precipitation: Odds favor drier-than-average conditions from South Florida and along the Gulf Coast through Texas and into the Southwest.Wetter-than-average conditions are favored across parts of the northern plains.
Drought: From the Southwest, across the South and northward to the mid-Atlantic, drought has been spreading and deepening since the winter and is forecast to persist in spring. Wildfires will be an increasing threat, especially when humidity is low and when winds are high.
Heavy rainfall at any time can lead to river flooding, even in areas where overall river flood potential is considered below average. Find current hydrologic information specific to your area at: http://water.weather.gov.
Floods are the deadliest weather phenomena - claiming an average of 100 lives annually. Many of these deaths occur in automobiles and are preventable. If confronted with a water-covered road on foot or in an automobile, follow National Weather Service advice: “Turn Around, Don't Drown.”
To read NOAA's seven-page National Hydrologic Assessment report, click HERE.
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