Raleigh, N.C. — As the remnants of Hurricane Sandy continue their slow trek through Pennsylvania and eventually upstate New York, southern power companies on Tuesday began sending hundreds of crews northward to help restore power to more than 6 million people without it in the hours after the superstorm made landfall. 

Exact power loss numbers for the whole region weren't available early Tuesday, but much of lower Manhattan in New York City and other heavily-populated areas in New Jersey and elsewhere were in the dark after the storm made landfall along the New Jersey coastline. Slideshow     Images: Superstorm Sandy roars into Northeast

Dozens of crews and more than 120 linemen from Georgia Power were staging at the North Carolina State Fairgrounds Tuesday morning, preparing for a trip to Baltimore.

Progress-Duke Energy will also send as many as 1,200 people north within the next 24 hours. Five-hundred employees from Progress Energy Florida will arrive in Virginia Tuesday to assist Dominion Power, and 500 crews from Duke Midwest will also travel east. 

As many as 240 contractors will also head to Virginia and the Mid-Atlantic area Tuesday, as power outages are expected to grow in the next two days as Sandy's remnants continue to dump heavy rain across several states. Some experts predict as many as 10 million customers could be without power by the time all is said and done. 

Reaching some of the hardest hit areas could be tough for crews, as flooded roadways on Long Island have made travel nearly impossible. Downed trees could also delay crews. Interactive     Sandy's impact: State-by-state

Snow in West Virginia, western Virginia and even North Carolina could also cause power outages, as some areas have seen multiple feet of snow since Sandy began impacting the area Sunday. Several counties in Western North Carolina were under a winter storm warning early Tuesday, and about 4,000 were without power in Henderson and Buncombe counties.

Sandy's remnants were expected to slowly move north through western Pennsylvania and upstate New York Tuesday and Wednesday, eventually crossing the U.S.-Canadian border late in the day Wednesday. The slow-moving storm could still dump several more inches of rain on already water-logged areas of the Northeast.