Two million homes and businesses were without power early today as Hurricane Irene slammed into the East Coast and charged north.

Winds of up to 115 miles per hour whipped across the Eastern Seaboard, ripping power lines from poles and snapping trees in half. Hospitals, emergency call centers and other crucial facilities were holding up, but officials said it could get much worse as Irene churns north.

Gasoline supplies were falling as drivers fill up before leaving town or just top off their tanks as a precaution before the storm hits. Pump prices rose about 3 cents per gallon overnight in New Jersey and Pennsylvania.

Dominion Resources reported outages for more than 900,000 of its customers in Virginia and North Carolina, while Progress Energy reported 190,000 customers without power.

Duke Energy said 1,500 customers were in the dark. Pepco, which serves Maryland, Washington D.C., parts of New Jersey and Delaware, reported nearly 80,000 outages. Baltimore Gas & Electric said nearly 250,000 of its customers were without power.

In eastern Pennsylvania, PECO reported nearly 140,000 customers without power.

New York’s biggest utility, Consolidated Edison, said it could cut power to the city’s most vulnerable areas if the storm causes serious flooding. Salt water and rain can damage electrical equipment.

ConEd operations chief John Miksad said the utility doesn’t expect to cut power before the storm hits, but flooding today could bring a shutdown to areas including the southern tip of Manhattan. That would cut off power to major Wall Street institutions through parts of next week.

The New York Stock Exchange has backup generators and can run on its own, a spokesman said. The exchange expects to open as usual Monday morning, though it may change plans depending on the severity of the storm.

New York is regularly blasted by winter storms, but Miksad said this hurricane will be different. Irene’s wind will pack a stronger punch than a nor’easter last March that knocked out power to 175,000 customers, he said.

ConEd has called in crews from as far as Colorado to help repair damage from the storm.

Irene is expected to be a brutal test for Middle Atlantic States, which haven’t seen a hurricane since 1999. The storm is expected 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, wind speeds diminish.

The entire Eastern Seaboard lies in the storm’s projected path. Flooding and damage from winds are likely. North Carolina, Virginia, Maryland, New Jersey, New York, Connecticut and Rhode Island have declared emergencies. For the first time, New York City ordered people in low-lying areas to evacuate.

Power companies have called in several hundred workers from surrounding states to help. Crews were rushing out between bands in the hurricane, when the wind and rain ease. They’re looking for damage first at towering transmission lines, where an outage could put an entire county in the dark.

The storm has already caused gasoline supplies to fall as refueling barges wait out the storm off the coast. Widespread power outages could lead to fuel shortages as gas stations are no longer able to pump gas or have trouble replenishing their own gas supplies.