New York Gov. Andrew Cuomo told the Metropolitan Transportation Authority to prepare to shut the city's subways, buses and suburban trains. The city closed the subways before Hurricane Irene last year, and a Columbia University study predicted that an Irene surge just 1 foot higher would have paralyzed lower Manhattan.
Up and down the Eastern Seaboard and far inland, officials urged residents and businesses to prepare in ways big and small.
On Saturday evening, Amtrak began canceling train service to parts of the East Coast, including between Washington, D.C., and New York. Airlines started moving planes out of airports to avoid damage and adding Sunday flights out of New York and Washington in preparation for flight cancellations on Monday.
The Virginia National Guard was authorized to call up to 500 troops to active duty for debris removal and road-clearing, while homeowners stacked sandbags at their front doors in coastal towns.
"You never want to be too naive, but ultimately, it's not in our hands anyway," said Andrew Ferencsik, 31, as he purchased plywood and 2-by-4 lumber from a Home Depot in Lewes, Del.
Utility officials warned rains could saturate the ground, causing trees to topple into power lines, and told residents to prepare for several days at home without power.
President Barack Obama was monitoring the storm and working with state and locals governments to make sure they get the resources needed to prepare, administration officials said.
In North Carolina's Outer Banks, a group of about 20 people was forced to wait out the storm on Portsmouth Island, a former fishing village that is now uninhabited and accessible only by private ferry.
"We tried to get off the island and the ferry service shut down on us," said Bill Rowley, 49, of Rocky Mount, N.C.
Rowley said he could see 15-foot seas breaking over the island's dunes, enough to bring water to the island's interior.
"We'll be inundated and it'll probably be worse tomorrow," he said.
In New Jersey, hundreds of coastal residents started moving inland. Christie's emergency declaration will force the shutdown of Atlantic City's 12 casinos for only the fourth time in the 34-year history of legalized gambling here. City officials said they would begin evacuating the gambling hub's 30,000 residents at noon Sunday, busing them to mainland shelters and schools.
The storm also forced the presidential campaign to juggle schedules. Romney scrapped plans to campaign Sunday in Virginia and switched his schedule for the day to Ohio. First lady Michelle Obama canceled an appearance in New Hampshire for Tuesday, and Obama moved a planned Monday departure for Florida to Sunday night to beat the storm. He also canceled appearances in Northern Virginia on Monday and Colorado on Tuesday.