BOSTON -- Bitter cold kept its grip on the Northeast on Saturday, while warmer temperatures brought relief to the Midwest and Southeast.

A day after schools in a dozen states closed and Alabama was colder than Alaska, temperatures in the South climbed into the 40s, thawing water fountains and pipes. Parts of the Northeast, however, persisted with temperatures barely in the teens.

In Boston, the Pine Street Inn shelter sent vans to look for the homeless during the day, rather than just at night, said shelter spokeswoman Barbara Trevisan. The shelter also expanded its hours and served an extra meal.

"From what I'm hearing, it's the coldest it's been in a number of years," she said.

Trevisan said the shelter, which holds about 700 people, has been packed in recent nights. Boston's low early Saturday was eight degrees, and temperatures hovered near zero elsewhere in the state.

In Illinois, the deep cold that seized the state for two days eased, leaving flooded rivers and frozen waterways in its wake.

Temperatures reached the low 30s in central Illinois and the low 20s in the northern part of the state Saturday -- balmy compared to the subzero weather that forced people to hide their grimaces behind scarves and ski masks. The National Weather Service said it had been the coldest episode in northern Illinois since February 1996.

At least five tow barges became locked in ice on the lakes near Peoria, said Mike Cox, operations manager with the U.S. Army Corps of Engineers' Peoria office. Ice also caused barge traffic to slow along the Illinois River.

In upstate New York, where some communities had dipped below minus 30 during the cold snap, midday temperatures Saturday only reached the mid-teens near the Canadian border. Plattsburgh, N.Y., broke the record low Friday at 24 below.