Washington DC and Baltimore are under blizzard warnings and states of emergency have been declared across the US East Coast as preparations were made for a storm expected to bring up to 75 cm of snow.
As the first major East Coast winter storm began dumping snow on the nation's capital, residents from North Carolina to New York were told to stay indoors, avoid travel and stock up on food and other necessities.
Shoppers cleared shelves in Washington-area stores, buying batteries, water and food.
Washington Mayor Muriel Bowser and New York Mayor Bill de Blasio urged motorists to stay off roads, starting on Friday.
"Anyone who has the illusion you're going to be taking big trips over the weekend, get that out of your mind," de Blasio said at a news conference.
Speaking at a news conference surrounded by dump trucks being loaded with salt, Bowser said the US capital's public schools would be shut on Friday and local government offices would close at noon.
Bowser apologised for not having the city ready for about 5cm of snow that snarled Wednesday's rush hour traffic.
The National Weather Service put Washington and Baltimore under blizzard warnings from Friday afternoon through to Sunday morning.
It forecast up to 60cm of snow in Washington, and as much as 75cm in western suburbs, with winds gusting to 80km/h.
"Visibility will be reduced to near zero in whiteout conditions," it said.
In North Carolina, two women died late on Wednesday from car accidents on slippery roadways, the governor's office said.
The storm was expected to deliver a slightly weaker wallop to the New York and Long Island areas with blizzard conditions from Saturday morning through Sunday.
Governors in Virginia, Maryland, North Carolina and Pennsylvania joined Bowser in declaring states of emergency.