The northeast of America is braced for a so-called "bomb cyclone" – or "bombogenesis" blizzard – as brutal weather conditions take hold of large parts of the US.
It comes after a winter storm in the southeast of the country saw heavy snowfall in Florida's capital Tallahassee for the first time in three decades.
Conditions are expected to become more severe in the New England region on Thursday as travel continues to be disrupted.
The weather led to states of emergency being declared in Florida, Georgia, North Carolina and Virginia.
The National Weather Service implemented blizzard warnings from Virginia to Maine with areas around Boston in New England forecast to see about 30cm (12 inches) of snow on Thursday.
The intensified "bomb cyclone" effect, which could see several inches of snow falling per hour, occurs when a storm's barometric pressure drops by 24 millibars in a day.
Trucks have been loaded with road salt ahead of the expected storm in the northeast and schools in New York have been closed in anticipation.
The city is expected to see up to 20cm (eight inches) of snow and winds of up to 50mph on Thursday as much of the east coast experienced sustained cold conditions, which has even frozen parts of Niagara Falls.
The weather has led to pipes freezing and water mains bursting, and caused chaos for firefighters.
At least nine people have died in the past few days, including two homeless people in Houston, with the freezing temperatures being blamed for the deaths.
A 96-year-old woman with dementia in Michigan was found dead in a playground on Wednesday – apparently freezing to death after wandering outside in a robe and slippers.
Scientist Judah Cohen at the Massachusetts Institute of Technology said the storm in the northeast would be particularly strong this year despite the region seeing harsh winters every year.
He said: "This one is unique in how quickly the pressure is going to fall. The pressures could rival a category one or category two hurricane."
Forecasters say an arctic air mass will remain over the eastern two-thirds of country until the end of the week.
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South Carolina's governor, Henry McMaster, warned those in the northeast to keep their pets indoors.
He said: "If they can't get in the heat, they'll freeze to death and they'll be gone, and the same thing will happen to people. So you have to be careful about that."