Heartland braces for threat of flooding

Flat, frosty Minnesota and the Dakotas, no strangers to overflows during the annual thaw, are all but certain to be inundated as waterways become engorged with melted snow and runoff from saturated soils, the National Weather Service says.

But this winter’s snowy barrage has enlarged the danger zone in the nation’s midsection, with prospects for flooding rated high or above average in river basins from northern Montana to St. Louis.

The lower Great Lakes could be another trouble spot. Melting snow and heavy rain threatened flooding in all 88 of Ohio’s counties last week. The town of Findlay was submerged. Waters up to 4 feet deep destroyed a building at Cleveland’s zoo and killed a peregrine falcon. An overflow creek forced about 200 people to be evacuated from their homes in the Lake Erie community of Sunset Bay, N.Y.

Much of the eastern United States has received more snow than usual, putting eastern New York state and southern New England at an elevated flood risk, according to the weather service. Connecticut has received more than 80 inches, and the snowpack ranges from 10 to 20 inches in Rhode Island, which last year suffered its worst flooding in two centuries because of torrential rainstorms.

Across much of the north-central region, the ground is “frozen, water-saturated, and snow-covered’’ and tributary streams are swollen, the weather service said in a recent report.

Computer models suggest the snowpack’s moisture level is among the highest in six decades.