High winds and heavy snow have barrelled into the US northeast, shutting schools and government offices, leaving tens of thousands without power and snarling travel as New York's JFK Airport halted flights due to whiteout conditions.
Thousands of flights were cancelled, snow ploughs and salt trucks were omnipresent on roads and highways, and commuters who braved the storm to head in to their jobs hoped they would be able to make it home safely as the storm intensified later in the day.
Blizzard warnings were in place along the coast from North Carolina to Maine, with the National Weather Service forecasting winds as high as 115km/h that may bring down tree limbs and knock out power.
More than 30 cm of snow was forecast for Boston and coastal areas in northern New England.
The storm is the product of a rapid plunge in barometric pressure that some weather forecasters are referring to as bombogenesis or a "bomb cyclone," which brings fast, heavy snowfall and high winds.
The wintry weather has been blamed for at least 13 deaths over the past few days, including three fatalities in North Carolina traffic accidents and three in Texas due to cold.
More than 3300 flights were cancelled ahead of the storm's arrival in the northeast on Thursday. At New York's three major airports and Boston's Logan International, as many as three out of four flights were called off, according to tracking service FlightAware.com.
New York's John F Kennedy International Airport temporarily halted all flights due to whiteout conditions, it said on its Twitter feed.
Passenger train operator Amtrak was running reduced service in the northeast, while mass-transit systems in major metropolitan areas, including New York and Boston, remained open.
The NHL game between Boston's Bruins and the Florida Panthers has been postponed.