A huge blizzard bearing down on the US east coast is expected to dump near-record levels of snow on Washington and the Mid-Atlantic region.

More than 50 million people have been warned of a "potentially paralysing storm" late on Friday that will bring 24ins (60cm) of snow within hours.

There are warnings the blizzard could cause power outages and will bring road and air travel to a halt.

A rush for supplies led to long queues and empty shelves at supermarkets.

The weather system has already proved to be deadly, with two drivers killed in North Carolina, one in Tennessee and a pedestrian dead in Maryland.

In summary:

- states of emergency declared in Maryland, North Carolina, Georgia, Pennsylvania, Virginia and the District of Columbia

- blizzard watches in effect from Arkansas through Tennessee and Kentucky and as far north as New York

- heaviest snowfall (24ins) predicted for area just west of Washington DC

- the capital's transport system - the second busiest in the US - will close all weekend

- Garth Brooks has postponed two sold-out concerts in Baltimore

- schools across the region are closed on Friday

- airlines have issued waivers for travel, meaning passengers can rebook

High winds could compound problems, with 30mph (50km/h) winds forecast for Manhattan on Saturday, and even stronger gusts in Washington and Baltimore.

National Weather Service director Louis Uccellini said the system had "the potential of being an extremely dangerous storm that could affect over 50 million people".

He added: "We are talking about a potentially paralysing storm that is already setting up."

The record snowfall for Washington is 28ins (71cm) that fell during a two-day period in January 1922.

Boston, which bore the brunt of repeated snowstorms last year, is expected to escape relatively lightly this time, with just a few inches.

A light dusting of snow on Wednesday night caused gridlock in Washington, raising fears about what lies ahead.

Routine commutes lasted up to three hours and some people abandoned their cars, after an inch fell - a fraction of what is expected on Friday and Saturday.

Washington Mayor Muriel Bowser tweeted an apology and even President Barack Obama's motorcade got snarled up in it, spending an hour and 12 minutes on a half-hour journey to the White House.

Snowfall predictions

• 24ins (60cm) - NE Virginia
• 20ins - Washington DC
• 12-18ins - Philadelphia
• 14ins - Kentucky
• 10ins - New York City and Long Island