Hurricane Irene's strong winds and heavy rains threaten to deliver long-lasting power outages to millions of customers along the East Coast, utility officials and weather forecasters say.

An unusually large number of people may be affected by Irene because it is forecast to stay just offshore -- and thus retain much of its power -- as it inches up the coast from North Carolina to New England. When a hurricane hits land, it quickly loses steam.

High winds are the biggest threat to utility wires and poles. Recent heavy rains in the region have made trees even more vulnerable to toppling over. Flooding can cause problems for power plants, which are often located near rivers or other bodies of water.

The path and strength of the storm is still uncertain. However, utilities are preparing for the possibility that outages will be widespread and lengthy.

"It's going to be really tough," says Karen Johnson, a spokesperson for PSE&G, which serves 2.2 million customers in New Jersey. She recommends customers stock up on supplies of food and water before the storm hits.