At least 16 people have died due to blizzard-like conditions battering the eastern half of the US, leaving nearly two feet of snow.
Around 1,900 flights have been cancelled across the country as howling wind and sub-zero temperatures wreaked chaos.
Governors in New York and New Jersey declared states of emergency and urged residents to stay at home, while hundreds of schools were shut down in Boston and New York.
New York Governor Andrew Cuomo said: “This is nothing to be trifled with. People should seriously consider staying in their homes.”
The deaths include those caused by difficult traffic conditions in Michigan, Kentucky, Indiana and Illinois.
A massive pile of salt fell on a worker at a Philadelphia storage facility, killing him. And authorities say a woman with Alzheimer’s disease froze to death after she wandered away from her rural New York home.
Forecasters say temperatures were plummeting to well below freezing, and wind chill readings could hit minus 10F (-23C).
Another wave of cold air was already blasting through the Midwest after moving down from Canada.
Outreach teams were searching streets in New York City and Boston for homeless people at risk of freezing to death.
Meanwhile, some major highways in New York state were shut down overnight, and some commuter trains around New York City were operating on a reduced schedule.
Amtrak planned to run trains on all of its Northeast lines on Friday but operate on a modified schedule, spokeswoman Christina Leeds said.
New Jersey Governor Chris Christie ordered non-essential state workers to stay at home, with state offices and courthouses closed.
The heavy weather began on Thursday, just a day after New York Mayor Bill de Blasio was sworn in to lead the nation’s largest city and a few days before Boston Mayor Thomas Menino ends 20 years in office.
Mr De Blasio, who in 2010 criticised predecessor Mayor Michael Bloomberg for his handling of a post-Christmas storm, said 1,700 snowplows and 450 salt spreaders were hitting the streets in New York City.
“We have to get it right, no question about it,” he said.
“We are focused like a laser on protecting this city.”