NEW YORK (Reuters)—A huge snowpack from a harsh winter will cause extensive flooding this spring in the upper Midwest and in the major corn-growing state of Iowa, the U.S. National Oceanic Atmospheric Administration said on Tuesday.

"We are looking at potentially historic flooding in some parts of the country this spring," NOAA administrator Jane Lubchenco told reporters in a briefing while presenting the government's spring flood risk outlook.

The snowpack in the Midwest is "more extensive than in 2009," with precipitation in December up to four times above average, NOAA said.

"It's a terrible case of deja vu, but this time the flooding will likely be more widespread," Ms. Lubchenco said. "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."

Of particular risk is the Red River Valley in Minnesota, with NOAA officials saying it was unusual that the area would face the threat of severe floods for the second year running.

The Red River runs north, dividing North Dakota and Minnesota, before running through the flat southern plains of the Canadian province of Manitoba.

The U.S. side of the valley is planted to wheat, soybeans and other crops. The Red River area is also the top growing region for sugar beets in the country.

"We're seeing an extraordinary snowpack in the Red River Valley," said Jack Hayes, director of the National Weather Service.

Areas of the country ranging from Texas to Maine also face an above-average risk of floods because of heavy snows and rains this winter.

Mr. Hayes added the possibility of flooding in the southern and eastern United States "will largely be dependent upon the severity and duration of additional precipitation and how fast existing snowcover melts."

The problem is that the ground is saturated in many areas and any more rain could easily cause floods in the south and eastern parts of the United States.

The forecasters said an El Niño weather anomaly was one of the reasons for the wet winter and spring in 2009-2010.

El Niño causes an abnormal warming of waters in the equatorial Pacific and wreaks havoc in weather patterns around the Asia-Pacific region.