Severe Spring Floods Forecast for Upper Midwest, South and East

WASHINGTON, DC, March 16, 2010 (ENS) – An unusually wet and snowy winter will increase the potential for spring flood events, the National Weather Service warned today. Seasonal flooding already has begun and is forecast to continue through spring in parts of the Midwest, said the meteorologists.

Forecasters said the South and East are more susceptible to flooding than usual this year as an El Nino influenced winter left the area soggier than usual.

Overall, more than a third of the area in the lower 48 states has an above average flood risk after one of the snowiest winter seasons in many years. December precipitation was up to four times above average.

Current flood map shows major flooding in purple, moderate flooding in red. (Map courtesy USGS)

The highest threat is in the Dakotas, Minnesota and Iowa, including along the Red River Valley where crests could approach the record levels set last year.

“It’s a terrible case of deja vu, but this time the flooding will likely be more widespread,” said NOAA Administrator Dr. Jane Lubchenco. “As the spring thaw melts the snowpack, saturated and frozen ground in the Midwest will exacerbate the flooding of the flat terrain and feed rising rivers and streams.

“We will continue to refine forecasts to account for additional precipitation and rising temperatures, which affect the rate and severity of flooding,” she said.

North Dakota Governor John Hoeven said Sunday that President Barack Obama has approved his request for a federal declaration for the state under the Disaster Relief and Emergency Assistance Act due to weather conditions and forecasts indicating a strong potential for severe spring flooding. Disaster relief was approved for North Dakota 18 counties and the Spirit Lake Nation reservation.

The state and many communities and counties are already allocating resources and preparing for widespread flooding.

Today, Governor Hoeven joined a group of Fargo South High School students to help pass sandbags from pallets into backyards of houses along the Red River in south Fargo. The sandbags are being used to create flood barriers in an effort to protect homes from the rising water of the Red River.

North Dakota Governor John Hoeven helps to place sandbags against the rising Red River. (Photo North Dakota National Guard)

In South Dakota, Governor Mike Rounds says 12 counties and two American Indian reservations will get federal financial assistance to help recover from the Christmas blizzard of 2009 through a presidential disaster declaration signed last week by President Obama.

“I’m pleased that federal aid has been promptly approved by the President,” Governor Rounds said. “Unfortunately, the area struck by the Christmas-period blizzard continues to be plagued by an excess of moisture. We are now monitoring rivers and streams that are at or near flood stage.”

Saturated soil conditions, high water content in the current snowpack, full ponds and wetlands that result in minimal available surface storage, and the prospects of additional moisture and ice jams through the spring snowmelt are all contributing to the flood forecast.

Until early March, consistently cold temperatures limited snow melt and runoff, and the ground is frozen to a depth as much as three feet below the surface, meteorologists said.

“In the South and East, where an El Nino-driven winter was very wet and white, spring flooding is more of a possibility than a certainty and will largely be dependent upon the severity and duration of additional precipitation and how fast existing snow cover melts,” said Jack Hayes, PhD, director of the National Weather Service.

“Though El Nino is forecast to continue at least through spring, its influence on day-to-day weather should lessen considerably,” said Hayes.

Without a strong El Nino influence, climate forecasting for the spring months April through June is more challenging, but NOAA’s Climate Prediction Center says odds currently favor wetter-than-average conditions in coastal sections of the Southeast.

The center predicts warmer-than-average temperatures across the western third of the nation and Alaska, and below-average temperatures in the extreme north-central and south-central United States.

This is Flood Safety Awareness Week, says Hayes, who is reminding all drivers across the country “Turn Around, Don’t Drown.

“It floods somewhere in the United States or its territories nearly every day of the year, killing approximately 100 people on average and causing nearly $7 billion in damages,” said Hayes. “Awareness, preparedness and action are the key ingredients to protecting lives and property when floods threaten.”

Roadway flooding can be deceptively deep, and it only takes six inches of water to lose control of a vehicle. It is imperative that people use extreme caution when driving at night, when it is difficult to determine if a road is flooded. It is also important to avoid areas that you know are already flooded, especially if the water is flowing fast.

To help community decision-makers and residents understand their risk, monitor threatening situations and take action when warranted, NOAA produces river and flood forecasts and warnings. Flood forecasts are available at www.weather.gov/water, and are also broadcast over NOAA Weather Radio All Hazards.

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