Hundreds of thousands of people along the US mid-Atlantic region should be bracing for “perhaps crippling” snow, the National Weather Service has said.
Forecasters say up to 16in (40.6cm) of snow could fall over the weekend in an area that spans big cities such as Washington and Philadelphia.
Blizzard warnings have been issued in some areas, warning of heavy winds and wet snow could lead to power outages.
Earlier storms on Wednesday left drivers in hours-long gridlock.
Crews have cleared roads in the Washington, Virginia and Maryland areas after a small storm left roads icy just ahead of rush hour commutes.
There were reports of otherwise routine short commutes lasting up to three hours, and of some people abandoning their cars.
However, National Weather Service forecasters are warning that Wednesday’s storms were just a prelude to a powerful storm that will hit the region on Friday and last until Saturday night.
The details of the coming storm remain uncertain.
When exactly the storm will begin and predictions of the amount of snow that will fall have varied.
“There’s a lot of details that are yet to be seen,” Rich Otto of the National Weather Service’s Storm Prediction Center said. “Subtle changes can make a big difference. We’ve seen that in storms in the past.”
Across the US east coast at a glance:
- grocery store queues are long with residents purchasing milk, laundry detergent and other necessities
- classes were cancelled at schools in Kentucky and Tennessee, the first states being affected by the storm
- major airlines are allowing travellers in affected regions to rebook onto flights ahead of or after the storm.
- Washington, DC Mayor Muriel Bowser has requested Humvees from the National Guard so that emergency responders can reach isolated people and places
- West Virginia Governor Earl Ray Tomblin has activated the National Guard to assist with the storm that could dump 2ft of snow in some parts of the state
- in Philadelphia, Pennsylvania officials are touting large salt stockpiles and plough vehicles in good repair
- in southern New England broadly, predictions are uncertain, but officials are preparing for up to 6in of snow