MIAMI: Hurricane Sandy lumbered north in the Atlantic Ocean on Sunday as Americans on the eastern seaboard scrambled to stock up on supplies and secure homes before the superstorm comes ashore with torrential rains and gale-force winds.

The so-called “Frankenstorm” was expected to make landfall somewhere between Virginia and Massachusetts on Tuesday, possibly causing chaos during the frenzied last days of campaigning before the November 6 US presidential vote.

As it churned in a northeasterly direction, the massive weather system was at category one hurricane strength, with maximum sustained winds of 75 miles (120 kilometers) per hour, the National Hurricane Center said.

The center said that while little change in strength was anticipated for Sandy over the next couple of days, it was “expected to remain a large and powerful cyclone.”

Forecasters at the National Weather Service warned that the storm would “result in significant impacts along coastal North Carolina” beginning on Saturday.

But emergency officials were far more worried about what could happen further north.

Sandy’s likely collision early next week with a seasonal “nor’easter” weather system was predicted to super-charge the storm, dragging it to the west where it is expected to slam into the coastal US states of Virginia, West Virginia, Pennsylvania, New York, New Jersey, Connecticut, Massachusetts and even inland Ohio.

Alex Sosnowski, an expert senior meteorologist for Accuweather.com, called Sandy “an extremely rare and dangerous storm,” menacing 60 million people that “could lead to billions of dollars in damage.” It could have the strength of a category one or two hurricane, he explained, but with powerful winds extending out hundreds of miles from the center.

Taking the dire predictions to heart, residents were bracing for huge tidal surges, power outages, inland flooding and even heavy snowfall on high ground far from the coast.

US President Barack Obama was briefed by top emergency officials on Saturday, the White House said, and governors declared states of emergency in Maryland, New York, New Jersey, Connecticut, Pennsylvania, Virginia, the US capital Washington and a coastal county in North Carolina.

Meanwhile, concern was also mounting that storm damage and power outages could have a major impact on voter turnout, polling station readiness and last-minute campaigning by Obama and his Republican rival Mitt Romney.

Obama already canceled two campaign events early next week to monitor developments related to Sandy.

Meteorologists have nicknamed the unusual confluence of weather patterns a “Frankenstorm,” because it is due to hit just before Halloween on October 31 and is composed of parts from different sources, as was Frankenstein’s monster.

The powerful hurricane earlier claimed 11 lives in eastern Cuba, including several people who died in the rubble of collapsed buildings.

On Wednesday, Sandy unleashed its wrath on Jamaica, where one person died, and on Haiti, where 44 people were killed according to an updated official toll. Two people were reported dead in the Dominican Republic and one in the Bahamas.