Everything You Need to Know About Deadly Snowstorm Bearing Down on East Coast

— -- A weekend snowstorm that has left at least three dead is hitting the eastern United States as of Saturday morning, with the possibility of record snowfall.

In North and South Carolina, almost 150,000 customers were without power, according to Duke Energy, and the Virginia State Police responded to 989 traffic crashes and 793 disabled vehicles on Friday alone.

A shelter opened for drivers in Kentucky after Interstate 75 shut down due to bad conditions. Kentucky State Police tweeted late Friday evening that emergency management teams were making their way to the stranded cars with water and fuel.

More than 6,800 flights have already been canceled for this weekend and cities are bracing for the worst.

Here's everything people on the East Coast need to know.

Fatalities

There have been three deaths in two states -- Virginia and North Carolina -- as result of this storm system Friday. All three were the result of car accidents.

Expected Snow Totals

- Washington, D.C.: In D.C. and Baltimore about 20 to 25 inches of snow is expected. If D.C. gets more than 20 inches of snow, this will be the biggest snowstorm since the blizzard of 1922 that left D.C. with 28 inches of powder.

- Philadelphia: Philadelphia is expected to get 18 to 24 inches of snow.

- Central NJ: Parts of central New Jersey could see up to 18 inches. Gov. Chris Christie declared a state of emergency for New Jersey Friday night.

- New York City: In New York City, 10 to 15 inches of snow is likely.

The Impact

Some 80 million Americans were expected to be impacted by the storm or bracing for the storm.

Winter Weather Alerts stretch from Mississippi to Massachusetts, spanning over 1,000 miles.

Blizzard Warnings

A blizzard watch is in effect for Washington; Baltimore, Maryland; Wilmington, Delaware; Philadelphia; Trenton, N.J.; Newark, N.J.; New York City; and Long Island.

Washington will be under a blizzard warning from 3 p.m. Friday to 6 a.m. Sunday.

In Philadelphia, the blizzard warning began at 7 p.m. Friday to 10 a.m. Sunday.

Snowfall was expected in the New York City area between 9 p.m. and 11 p.m. The storm will pick up in intensity by early Saturday morning.

The New York City blizzard warning will last from 6 a.m. Saturday to 1 p.m. Sunday.

A Potentially Deadly Storm for D.C.

D.C. Mayor Muriel Bowser said Friday morning that residents need to treat the storm as a life and death weather event.

"We’ve had a forecast we haven’t seen in 90 years,” Bowser said at a news conference. "It has life and death implications."

The mayor warned of high winds and potential power outages from trees taking down electrical lines.

“Our chief concern is making sure Washingtonians are safe throughout this event,” Bowser said, adding that “people need to stay inside” and not risk going out in the storm.

The city is asking residents to be prepared to stay indoors for 72 hours. Residents are also being asked to stay off the roads and stock up on food, water, battery operated radios and flashlights in case of power outages.

Problems in the South and on the Coast

As the storm was expected to move east Friday afternoon, heavy ice accumulation could cripple places like Charlotte, North Carolina; Raleigh, North Carolina; and Greenville, South Carolina.

In North Carolina, over 67,000 customers were without power as of 5 p.m. Friday, said North Carolina Emergency Management.

The state had about 1,274 reported traffic collisions, according to the North Carolina Highway Patrol.

On Friday evening, the storm was to bear down on the East Coast, from Virginia to New Jersey.

A coastal flood warning was issued for Virginia, New Jersey and the southern coast of Long Island.

Wind gusts could top 60 miles per hour this evening.

The worst coastal flooding and erosion will be in southern New Jersey, where some areas could see record flood levels. Waves up to 20 feet are possible along the Jersey shore.

A Winter Weather Emergency in NYC

A winter weather emergency will be in effect in New York City, starting at 8 a.m. Saturday morning and lasting until Saturday night at midnight, Mayor Bill de Blasio announced Friday.

The mayor said he might extend the emergency depending on conditions.

A winter weather emergency means any unnecessary driving should be avoided, he said.

"Unless it is urgent - stay off the roads," de Blasio said.

The mayor clarified that this is not a travel ban, which was instituted last winter during a snowstorm.

"This is less intense but still very, very serious," he warned.

"Stay off the roads tomorrow," he said. "If your vehicles are blocking the work of our snow plows, your vehicles will be towed."

Besides the heavy snow and strong winds, de Blasio said the city can expect whiteout conditions.

The brunt of the storm is expected to happen between 8 a.m. and mid-afternoon Saturday, but could continue Sunday morning, he said. About 12 to 18 inches is expected, the mayor said, although ABC News meteorologists predict slightly less.

A coastal flood warning is also in effect in New York City.

Flight Cancellations

In total, airlines have cancelled over 9,000 flights for Friday, Saturday and Sunday, according to FlightAware.com.

The Philadelphia airport has cancelled all flights for Saturday.

The Baltimore Office of Emergency Management tweeted late Friday evening that all flight operations at BWI Marshall Airport have ceased due to the inclement weather.

ABC News' Max Golembo, Dan Peck and Margaret Chadbourn contributed to this report.

Editor's Note: An earlier version of this story reported 9 dead. We have since corrected the number to 3.

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