The heavy snow toppled trees and sagged power lines, leaving more than 350,000 people without electricity in Maryland and neighbouring Virginia.
"The roads are very difficult to travel ... and we are seeing a spike in power outages," Ed McDonough, from the Maryland Emergency Management Agency, said.
"We are telling local residents to stay home, enjoy the time with their families and let the highway crews do their work."
Police in Virginia had responded to about 3,167 calls for help by Saturday, more than two-thirds of which were due to car accidents or stranded vehicles.
A father and son died in the state a day earlier, after being hit by a tractor-trailer while trying to help the driver of another vehicle on a busy highway.
Most flights were cancelled on Saturday at the Washington-Baltimore area's three main airports and at Philadelphia International Airport.
Transport links between Washington and its heavily populated suburbs were snapped, with most major roads impassable, knocking out bus services.
But some people were determined to enjoy the winter's second biggest storm in the area, with 5,000 turning out for a mass snowball fight in central Washington.
Electricity was cut in many homes and offices in Washington DC - including Al Jazeera's broadcast centre - as power lines were knocked out by the powerful storm.
Al Jazeera's Todd Baer, reporting from Washington DC, after the snowfall stopped, said the storm had left a "real mess".
"This is when the hard part begins - the clear-up, the ploughing of the streets, the opening of the businesses, and perhaps most importantly, getting power back to around 200,000 people in Washington DC and the surrounding area," he said.
Residents in the affected areas have taken to referring to the storm online as a "snowpocalypse" or "snowmageddon", including on social networking site Twitterand Flickr- a photo-sharing website.
Further west, mudslides touched off by torrential rains damaged dozens of homes and destroyed several others in the foothills above Los Angeles.
There were no reports of deaths or injuries, but residents said a wall of mud, rock
and debris came crashing down in the early hours of Saturday, carrying off cars and leaving a path of destruction in its wake.
The same storm system hit Mexico, killing at least 29 people as heavy rains caused rivers to burst their banks and flood roads.
Parts of the country have received eight times more rain in the past four days than they normally get in a month.
"The storm in Mexico and the storm in the US are actually part and parcel of the same storm," Steff Gaulter, Al Jazeera's meteorologist, said.
"It started off over Mexico, then headed north over Texas and the southeast of the United States, and is now giving blizzards to the east coast.
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