Some East Coast residents still recovering a year after being battered by Hurricane Irene are bracing for an even bigger storm.

Forecasters are warning that Hurricane Sandy will blend with two winter weather systems and form a rare megastorm that could spawn damaging winds, nearly a foot of rain and up to 2 feet of snow in some locations. Experts warn such a storm has the potential to be wider and stronger than Irene, which caused more than $15 billion in damage.

Some officials in seaboard states and cities have already declared states of emergencies. Residents are being warned they could go without power for several days.

The approaching storm has prompted the military to move some vessels out a major base in Virginia. Utilities have boosted manpower to ratchet up their storm response capability. Some airlines are saying they won't charge fees for passengers forced to change their plans.

The presidential campaign is also being impacted. Republican challenger Mitt Romney and Vice President Joe Biden have both canceled weekend events in coastal Virginia Beach, Va.

Sandy has just left the Bahamas. It's blamed for at least 40 deaths in the Caribbean. Residents from Florida to North Carolina will experience peripheral impacts of the hurricane through the weekend.