With further havoc expected today, Hurricane Isabel delivered its promised punch last night, lashing Maryland with high winds and heavy rain that caused flooding across the state and knocked out power for hundreds of thousands.

The storm claimed one victim yesterday afternoon.

It also caused the closing of the Bay Bridge and the cancellation of all flights at Baltimore-Washington International Airport.

By midnight, storm water was thigh-high at Thames and Wolfe streets in Fells Point in Baltimore - and as deep on the north side of the Inner Harbor. Much of the Pratt Street Pavilion walkway was under water, with the cement barriers around the World Trade Center resembling small islands. Water was also surging over the seawall onto the City Dock in Annapolis.

But other flood-prone areas - including Allegany County and Frederick - were still bracing for the storm's worst.

In some areas, including Ocean City, the storm seemed to have veered past without as much damage as feared. In others, such as Western Maryland, the biggest thrust hadn't arrived yet.

"The worst is yet to come," Todd Miner of the Penn State Weather Communications Group in State College, Pa., said yesterday evening.

Adding insult to injury, the storm spawned a tornado that touched down near Newark in Worcester County about 6:30 p.m., the National Weather Service reported. But the tornado, which was preceded by another in Norfolk, Va., caused no reported damage.

Far more trouble was caused by Isabel's winds, which knocked trees and limbs onto power lines, plunging many Maryland residents into darkness. By midnight, Baltimore Gas and Electric Co. reported that 330,000 customers were without power, including 114,000 in Baltimore County and 107,000 in Anne Arundel County.

Also affected were 33,000 in Baltimore, 23,000 in Harford County, 20,000 in Howard County and 9,000 in Carroll County. The outages even hit the emergency operations centers in Howard and Baltimore counties, which briefly went dark before their generators kicked in.

BGE, which serves 1.1 million customers in Central Maryland, had 800 crews - including 400 from across the country - trying to repair lines.

The Washington area fared as badly. Potomac Electric Power Co. said 220,000 of 720,000 customers in Washington and in Montgomery and Prince George's counties reported power outages.

Statewide, 609,000 had lost power by 11:30 p.m. "For many, the only light they're going to see is when the sun comes up," said Major Gen. Bruce Tuxill, head of the Maryland National Guard.

Residents had voluntarily evacuated from Solomons, Ocean City and Cambridge, among other places, officials said at a State House briefing last night. More than 1,800 residents had sought refuge at shelters set up throughout the state.

Around midnight, Anne Arundel County's Emergency Operations Center urged the voluntary evacuation of about 700 residents in eight waterfront communities, from West River south to the county line, out of concern about flooding with rising tides from the Chesapeake Bay.

Meanwhile, Charles County officials were trying to decide late last night whether to forcibly evacuate residents of Cobb Island who were refusing to leave.

The first storm-related death in Maryland was reported in Anne Arundel, where a man's car crashed into a telephone pole in Arnold about 4:30 p.m. The pole cracked into three pieces, one of which smashed through the car's windshield and instantly killed the driver.

Anne Arundel firefighters attributed the death on Shore Acres Road to driving rain and winds that forced the driver, whose identity was not released, to lose control of his car.

For much of the day, Isabel's arrival in central Maryland seemed slow and gentle compared with the dire warnings: The skies turned a steely gray and eerie breezes swirled, but rain was light in many areas. With most schools and many businesses closed for the day, it seemed possible that the state had fallen victim to overreaction.