Washington DC is among several cities preparing for the "Jonas" snowstorm
The Washington DC area is hunkering down for a direct hit from one of the worst snowstorms ever forecast to hit the nation's capital.
The weather system, named "Jonas" by the Weather Channel, is shutting down the city for the whole weekend.
Schools were closed on Friday and government offices shuttered at noon, prompting an exodus to the suburbs for legions of federal workers.
DC Mayor Muriel Bowser told a Friday news conference: "I want to be very clear with everybody: we see this as a major storm.
"It has life or death implications … hunker down, shelter in place, stay off the roads."
There was little sign of any calm before the storm, as hordes of shoppers flocked to ransack supermarket shelves of bread, milk and toilet paper.
A number of petrol stations in the suburbs are running low on regular gasoline, or have sold out altogether, because of panic buying.
Snow shovels and snow blowers have been cleared from the aisles of hardware stores.
The blizzard is threatening to dump as much as 29in of snow, which would surpass the city's deadly 1922 Knickerbocker storm.
The DC Metro, the second-busiest subway in the US, closes on Friday night for the entire weekend in its first such stoppage since Hurricane Sandy in 2012.
The traffic chaos that ensued on Wednesday night after a salt-shaker sprinkling of snow - just an inch - caught authorities unawares.
They're not taking any chances now.
The city is dispatching convoys of snow ploughs, salt trucks and gritters to make streets passable.
But the whiteout conditions and strong winds are expected to make travel highly hazardous.
Beer, wine and liquor sales have skyrocketed as householders organise #blizzard2016 parties.
Steve Levan, manager of Beer Wine & Co in the Chevy Chase area, told Sky News: "Business is three times what it normally is.
"Customers are buying whole cases of wine, multiple six-packs of beer, stocking up to spend days cooped up inside."
In Washington, Baltimore, and Delaware, archdioceses reminded people that the storm is a legitimate excuse to skip Sunday Mass.
Airlines have been cancelling flights in and out of the region's three major airports.
But there is good news for tobogganers.
They'll be allowed to go sledding this year on Capitol Hill, after a recent act of Congress overturned a ban in place since 1876.