A U.S. snowstorm with hurricane-force winds blasted much of East Coast on Saturday, paralyzing the nation's capital and its largest city.

Heavy snow started falling across more than 20 states in the U.S. on Friday. The storm, which is considered as the worst in history, has also turned deadly, with at least 18 reported deaths in the states of Tennessee, Kentucky, Maryland, North Carolina and Virginia.

More than 60 million people were under blizzard while more than 80 million were in the storm's path. As the storm roared up the East Coast, some 250,000 residents were without power. USA Today reported eleven states from Georgia to New York declared states of emergency.

Due to the severity of winter storm Jonas, more than 6,680 flights were cancelled for Saturday and Sunday, CNN reported. All flights were also halted at four of the country's busiest airports on Saturday including Philadelphia, Washington Dulles, Washington Reagan National and Baltimore/Washington International. Public transportations were also shut down while tunnels and bridges into New York were closed.

"This event has all the makings of a multibillion-dollar economic cost," said meteorologist Steven Bowen of Aon Benfield, a London-based global reinsurance firm. "We're potentially looking at one of the costlier winter storm events in recent memory."

The City of New York has also enforced a road travel ban. Officials have estimated up to 30 inches of snow to fall in parts of the state, which has already seen major breakdowns in the extreme weather pounding the East Coast. The city was also on alert for coastal flooding due to high tides, with resources being "prioritized" for the Long Island and New York City areas, The Independent noted.

While heaviest snow was engulfing New York City on Saturday, it was expected to ease by early afternoon, though not end until Sunday.

The winter storm has also dumped nearly 58 centimeters of snow on Washington, D.C. Several states were aiming to get a handle on highways obstructed by the drifting snow as well as to shore up coastal areas where the blizzard conditions raised threats of flooding.

National Weather Service meteorologist Greg Gallina said that high winds also battered the region, reaching 110 kilometers per hour in Wallops Island, Virginia, late Friday.

In New Jersey, the storm elevated flood waters in communities up and down the Atlantic Coast Saturday, closing roads and prompting evacuations. As per Chicago Tribune, the first round of flooding came with the morning tide.

The water started overflowing into streets in some towns again Saturday night. Fortunately, officials said the nighttime flooding wasn't expected to be as severe. A string of resort towns was also temporarily isolated Saturday morning by floodwater that swamped homes and restaurants.

Meanwhile, the record high of 71 centimeters of snow in the nation's capital was set in 1922 and the deepest recent.