Even if Sandy loses strength and makes landfall as something less than a hurricane, the combined superstorm was expected to bring misery to a huge section of the East. An 800-mile wide swath of the country could see 50 mph winds regardless of Sandy's strength.
Experts said the storm could be wider and stronger than Irene, which caused more than $15 billion in damage, and could rival the worst East Coast storm on record. On Saturday morning, forecasters said hurricane-force winds of 75 mph could be felt 100 miles away from the storm's center.
Up and down the coast, people were cautioned to be prepared for days without electricity. Several governors, including Connecticut's Dannel Malloy and New Jersey's Chris Christie, declared states of emergency. And airlines said to expect cancellations and waived change fees for passengers who want to reschedule.
Mandatory evacuations were under way in southern New Jersey's barrier islands, which people were ordered to leave by Sunday afternoon, and Christie ordered the evacuations of all Atlantic City casinos and said state parks would close.
"We should not underestimate the impact of this storm and not assume the predictions will be wrong," Christie said during a storm briefing Saturday in North Midletown, near the coast. "We have to be prepared for the worst."
In North Carolina's Outer Banks, light rain was falling Saturday and winds were building up to a predicted 30 to 50 mph. Gov. Beverly Purdue declared a state of emergency for some coastal areas, and a steady stream of campers and other vehicles hauling boats left the low-lying islands for the mainland. Residents feared a temporary bridge built after Irene last year poked a new inlet through the island could be washed out again, severing the only road off Hatteras Island.
In Ship Bottom, N.J., Russ Linke was taking no chances Saturday. He and his wife secured the patio furniture, packed the bicycles into the pickup truck and headed off the island.
"I've been here since 1997, and I never even put my barbecue grill away during a storm, but I am taking this one seriously," he said. "They say it might hit here; that's about as serious as it can get."
After Irene left millions without power, utilities were taking no chances and were lining up extra crews and tree-trimmers. Wind threatened to topple power lines, and trees that still have leaves could be weighed down by snow and fall over if the weight becomes too much.
New York City began precautions for an ominous but still uncertain forecast. No decision had been made on whether any of the city's public transportation outlets would be shut, despite predictions that a sudden shift of the storm's path could cause a storm surge of 3 to 6 feet and send water into the subway system.
The subway system was completely shuttered during Irene, the first such shutdown ever for weather-related reasons. Irene largely missed Manhattan but struck Brooklyn hard.
The storm loomed a little more than a week before Election Day, while several states were heavily involved in campaigning, canvassing and get-out-the-vote efforts. Republican presidential nominee Mitt Romney and Democratic Vice President Joe Biden canceled weekend campaign events in coastal Virginia Beach, Va., though their events in other parts of the states were going on as planned. In Rhode Island, politicians asked supporters to take down yard signs for fear they might turn into projectiles in the storm.
Sandy killed more than 40 people in the Caribbean, wrecked homes and knocked down trees and power lines.
Early Saturday, the storm was about 355 miles (571 kilometers) southeast of Charleston, S.C. Its sustained wind speed was about 75 mph (121 kph).
Sandy was projected to hit the Atlantic Coast early Tuesday. As it turns back to the north and northwest and merges with colder air from a winter system, West Virginia and further west into eastern Ohio and southern Pennsylvania are expected to get snow. Forecasters were looking at the Delaware shore as the spot the storm will turn inland, bringing 10 inches of rain and extreme storm surges, said Louis Uccellini, environmental prediction director for the National Oceanic and Atmospheric Administration.
Up to 2 feet of snow was predicted to fall on West Virginia, with lighter snow in parts of Ohio and Pennsylvania.
Jeff Masters, meteorology director of the forecasting service Weather Underground, said this could be as big, perhaps bigger, than the worst East Coast storm on record, a 1938 New England hurricane that is sometimes known as the Long Island Express, which killed nearly 800 people.
While rains were light Saturday in North Carolina's Outer Banks, winds were building up to a predicted 30 to 50 mph and a steady stream of campers and other vehicles hauling boats or with kayaks strapped to the roof were headed off the low-lying islands to the mainland. Local residents were preparing for power outages lasting days and fearing a temporary bridge built after Hurricane Irene poked a new inlet through the island last year could be washed out again, cutting off the only road out of Hatteras Island.
Retirees Larry and Jean Collier, of Brantford, Ontario, were leaving their beachfront hotel in Kill Devil Hills, N.C., early Saturday and trying to plot their route home knowing they risked driving into a mess.
"I'll try to split (the trip) right down the middle, not too close to Washington, not too far west," Larry Collier said. "The storm has kind of put a wrench in it."
Others were shrugging off dire predictions. Warren Ellis and his 10-foot-long camper were stuck on an uninhabited Outer Banks island on his annual fishing pilgrimage, the conditions too rough Saturday for the ferry to carry him to safer ground.
"We might not get off here until Tuesday or Wednesday, which doesn't hurt my feelings that much because the fishing's going to be really good after this storm. It's always good after a storm," said Ellis, 44, of Amissville, Va.
Dalesio reported from Kill Devil Hills, N.C. Associated Press writers Brock Vergakis in Duck, N.C., Frank Eltman in Freeport, N.Y., George Walsh in Albany, N.Y., Joe Mandak in Pittsburgh, Kathy Matheson in Philadelphia, Seth Borenstein in Washington and Christine Armario in Miami contributed to this report.