NEW YORK (ABC) -- As Hurricane Sandy loomed off the East Coast, some residents of New Jersey were warned to prepare for 7- to 10-day power outages, and portable generators are selling out all up and down the Atlantic Seaboard as people prepare for the worst.

Sandy is expected to combine with a cold front coming from the northwest and a high pressure system from Greenland, fueling it with enough energy to make it more powerful than the "Perfect Storm" from 1991, Hurricane Grace, some meteorologists say.

It is expected to wreak havoc on the East Coast and as far inland as Ohio for 48 to 60 hours with high winds, nearly a foot of rain and up to two feet of snow, ultimately affecting 50 million to 60 million people.

"The predictions on this storm and the damage it could create are dire," said Ron Morano, a spokesman for Jersey Central Power and Light, which issued the dire warning to its customers. "We need to deal with the forecast. We have said throughout that we are preparing for the worst case scenario."

Click here for more coverage from ABC News.