PORTLAND, Maine – A teeth-chattering cold wave with subzero temperatures is expected to keep its icy grip on much of the eastern U.S. into the weekend before seasonable temperatures bring relief.

A polar air mass blamed for multiple deaths in the Midwest moved into the Northeast on Wednesday, prompting the National Weather Service to issue wind chill warnings across upstate New York and northern New England and creating problems for people still trying to rebound from Superstorm Sandy.

In a storm-damaged neighborhood near the beach on New York City's Staten Island, people who haven't had heat in their homes since the late October storm took refuge in tents set up by aid workers. The tents were equipped with propane heaters, which were barely keeping up with the cold, and workers were providing sleeping bags and blankets for warmth.