SHIP BOTTOM, N.J. (AP) — Forget distinctions like tropical storm or hurricane. Don’t get fixated on a particular track. Wherever it hits, the behemoth storm plodding up the East Coast will afflict a third of the country with sheets of rain, high winds and heavy snow, say officials who warned millions in coastal areas to get out of the way.

‘‘We’re looking at impact of greater than 50 to 60 million people,’’ said Louis Uccellini, head of environmental prediction for the National Oceanic and Atmospheric Administration.

As Hurricane Sandy trekked north from the Caribbean — where it left nearly five dozen dead — to meet two other powerful winter storms, experts said it didn’t matter how strong the storm was when it hit land: The rare hybrid storm that follows will cause havoc over 800 miles from the East Coast to the Great Lakes.

Governors from North Carolina, where steady rains were whipped by gusting winds Saturday night, to Connecticut declared states of emergency. Delaware ordered mandatory evacuations for coastal communities by 8 p.m. Sunday.

New Jersey Gov. Chris Christie, who was criticized for not interrupting a vacation in Florida while a snowstorm pummeled the state in 2010, broke off campaigning for Republican presidential nominee Mitt Romney in North Carolina on Friday to return home.

‘‘I can be as cynical as anyone,’’ said Christie, who declared a state of emergency Saturday. ‘‘But when the storm comes, if it’s as bad as they’re predicting, you’re going to wish you weren’t as cynical as you otherwise might have been.’’

Eighty-five-year-old former sailor Ray Leonard agreed. And he knows to heed warnings.

Leonard and two crewmates in his 32-foot sailboat, Satori, rode out 1991’s infamous ‘‘perfect storm,’’ made famous by the Sebastian Junger best-selling book of the same name, before being plucked from the Atlantic off Martha’s Vineyard, Mass., by a Coast Guard helicopter.

‘‘Don’t be rash,’’ Leonard said Saturday from his home in Fort Myers, Fla. ‘‘Because if this does hit, you’re going to lose all those little things you've spent the last 20 years feeling good about.’’

Sandy weakened briefly to a tropical storm Saturday but was soon back up to Category 1 strength, packing 75 mph winds. It was about 275 miles south-southeast of Cape Hatteras, N.C., and moving northeast at 14 mph as of 2 a.m. Sunday, according to the National Hurricane Center.

The storm was expected to come ashore late Monday or early Tuesday in the mid-Atlantic, before reaching southern New England later in the week.

It was so big, however, and the convergence of the three storms so rare, that ‘‘we just can’t pinpoint who is going to get the worst of it,’’ said Rick Knabb, director of the National Hurricane Center in Miami.

Officials are particularly worried about the possibility of subway flooding in New York City, said Uccellini, of NOAA.

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.