Forecasters said it would remain chilly through the weekend in the mid-Atlantic, with daytime highs around freezing and overnight lows in the teens. Light snow was expected over the weekend.
Officials pleaded with people not to use generators or gas grills indoors after 20 to 25 people in the Philadelphia area were taken to hospitals with carbon monoxide poisoning.
Several hospitals were running on backup generators. Most decided to cancel elective surgeries and out-patient testing.