While the northern Plains and Northeast shiver in dangerously cold temperatures, the folks in upstate New York are keeping warm shoveling snow — lots of snow.

Since Sunday, the small towns of Parish and Mexico have recorded more than 6 feet of snow, and forecasters with the National Weather Service say it isn't over yet.

The area received short reprieve Thursday as the squalls shifted south into Syracuse, where between 4 and 8 inches fell. The lake-effect bands were expected to move back north overnight and strengthen.

"We're just trying to keep up. It's almost an unreal amount," said Mayor Randy Bateman of Oswego, where 70 inches of snow had fallen by Thursday morning. "We catch up when it stops, but then it just comes again, even heavier."

Gov. Eliot Spitzer declared a state disaster emergency for the county Thursday, authorizing all state agencies to help assist municipalities and residents in the storm-wracked region along eastern Lake Ontario.

Whiteout conditions — the snow has been falling at a rate of 5 inches an hour at times — forced state police to temporarily close Interstate 81 between Central Square and Pulaski, a stretch of about 15 miles. Travel advisories against unnecessary travel were posted for Oswego and its neighboring counties. Mexico officials renewed a snow emergency declaration, and many government offices were closed.

Schools were closed for a fourth day in Oswego and Mexico.

Temperatures in the Northeast inched back up to something closer to normal for this time of year, but the upper Midwest and northern Plains still awoke to subzero temperatures Thursday — minus-12 in Minneapolis and 3 below zero in Chicago.

The bitter cold and slippery roads have contributed to at least 20 deaths — five in Ohio, four in Illinois, four in Indiana, two in Kentucky, two in Michigan, and one each in Wisconsin, New York and Maryland, authorities said.