The storm claimed one victim yesterday afternoon.
It also caused the closing of the Bay Bridge and the cancellation of all flights at .
By midnight, storm water was thigh-high at Thames and Wolfe streets in in Baltimore - and as deep on the north side of the . 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 .
But other flood-prone areas - including Allegany County and Frederick - were still bracing for the storm's worst.
In some areas, including , 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, 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 .
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.
But conditions worsened as the day progressed, and forecasters expect Isabel to live up to its billing today.
Overnight winds were expected to gust as high as 70 mph in the Baltimore-Washington region as the storm tracked north-northwest. Tidal flooding was possible as winds shifted toward the southeast, especially around high tide early today.
With another band of rain forecasted to pass through the state early this morning, a total of 3 to 6 inches of rain was likely in the metropolitan areas, with as many as 10 inches expected farther west.
Authorities were most concerned about flooding in Allegany and Washington counties in Western Maryland, where the storm's center was expected to pass. Gov. Robert L. Ehrlich Jr. said 630 National Guardsmen had been dispatched, many of them to Hagerstown, and 30 water-rescue workers from Kentucky were headed to Cumberland. He said the state has 540,000 sandbags ready.
"We've never been as prepared for a storm as we were for this one," Tuxill, of the National Guard, said last night. That was good, he added, because "this has the possibility to be a 100-year storm."
Officials at the Maryland Emergency Management Center also worried last night about the possibility of a troubling confluence of events in Baltimore: that the storm surge could combine with the 2 a.m. high tide to breach the Baltimore seawall.
Flooding was well under way at the City Dock in last night, as a second surge of winds pushed water a foot deep along Dock Street. Over the protests of customers, a police officer shut down a "hurricane party" in a bar along the flooding street at 10:20 p.m.
By 5 p.m., winds were blowing steadily at 37 mph in , with gusts to 52 mph. More than 4 inches of rain had fallen. At BWI, the wind reached 28 mph with gusts to 35 mph.
At 9 p.m., the National Weather Service downgraded Isabel from a hurricane to tropical storm.
Throughout last night, the storm was expected to track north and west across central Virginia, reaching the vicinity of Cumberland by 8 a.m. today.
School is canceled across the region today, and state government offices are closed.
The forecast called for more rain, possible heavy at times, in the Baltimore area today. Winds of 30 mph, with gusts as high as 55 mph, were expected, diminishing to 21 mph to 24 mph later in the day. Skies should begin to clear this afternoon, becoming partly cloudy by tonight. A sunny weekend is predicted.
As the storm began battering the eastern edge of North Carolina and Virginia late yesterday morning, residents in Maryland tried to go about their day while keeping a close watch on the skies. Many workers were sent home early to avoid being caught in the wind and rains.
The storm struck early in Southern Maryland, where rain was coming down by mid-morning. On Rodo Beach, on the southern tip of St. Mary's County along the , Erik and Tracy Barkhimer were planning to ride out the storm with their tenant, Dave Murphy. That was before the bay rose above its seawall and into the yard before 4 p.m. - long before high tide was supposed to hit.
"That's when we said it was time to go," Erik Barkhimer said.
Last night, they hunkered down with beer and chicken in a hotel more than a dozen miles inland and hoped for the best.
Elsewhere in St. Mary's, where 19,000 were without power last night, several thousand residents were evacuated late in the afternoon, mostly from low-lying areas and from a few mobile home parks, said Rise Carter, assistant to the county administrator.
Not all bayside residents were playing it safe, though: In the late afternoon, Department of Natural Resources police responded to a report that five Naval Academy midshipmen had swum to a buoy off Cape St. Clair, state officials said. The swimmers made it back to shore safely.
And off Pocomoke City on the Eastern Shore, police went after a windsurfer who agreed to come off the bay only under the threat of arrest.
The 4.3-mile Bay Bridge was closed about 3 p.m. after winds reached 59 mph - the first storm-related closure in the bridge's 50-year history. The nearby Kent Narrows Bridge also was shut down.
"It was done to avoid injuries or possible fatalities," said state Transportation Secretary Robert L. Flanagan, adding that a tractor-trailer overturned on the Bay Bridge in 1999 during Tropical Storm Floyd, when wind gusts reached 81 mph at the bridge.
Flanagan said the bridge would reopen when sustained winds drop below 50 mph and it is clearly safe to cross.
Drivers caught on the Kent Island side of the bridge just after the closing were left searching for alternate routes or lodging.
New Jersey residents Tom and Grace Hoffman were returning from a week in when they were turned back at the bridge.
"I think if we'd have been there five minutes earlier, we'd have made it," said Tom Hoffman, 69. The couple decided to take a two-hour detour through Cecil County to return to their daughter's home in Gaithersburg.
At BWI, all arriving and departing flights were canceled after 5:30 p.m. yesterday, though scores of earlier flights also were scratched as Isabel disrupted air traffic across the country.
Flanagan said BWI flights are expected to resume at 8:30 a.m. today.
The Maryland Transit Administration, which canceled commuter and light-rail train service yesterday, discontinued its Metro subway runs at 2 p.m. out of what officials called an abundance of caution.
Amtrak canceled all trains south of Washington yesterday and today. Eastbound trains from Chicago also were canceled yesterday, but Amtrak continued normal service in the Northeast Corridor until 4:30 p.m., after which only a few trains left Washington for New York.
The travel cancellations made for weary travelers at Baltimore's Penn Station, and for a nearly deserted BWI.
Debbie McCune of Idaho said she has been through tornadoes, earthquakes, blizzards and floods, but never a hurricane. Because her flight home was canceled yesterday, she figured she was about to find out what one is like.
"I'm stranded until Saturday morning," said McCune, 40, who was supposed to leave Baltimore on a 2:40 p.m. flight.
Ehrlich ordered that state offices be closed to all but essential personnel about 1:30 p.m. yesterday. Touring Anne Arundel's Emergency Operations Center yesterday afternoon, he promised to deploy an additional 6,000 National Guard troops if necessary.
"We're accustomed to large snowstorms," Ehrlich said. "We're not accustomed to flash floods that can be brought about by 4 to 8 inches of rain. That is a lot of rain."
One factor reassured the governor: the lack of traffic on the streets. "People really do listen" to warnings, he said.
In Baltimore, Mayor Martin O'Malley said the dangers of flooding would persist even after the worst of the storm had passed. "We will be dealing with the threat of floods for the next 48 hours," O'Malley said.
Four city firehouses, one for each quadrant of the city, were equipped with boats that could be transported by trailers to areas of flash flooding. O'Malley said 40 to 45 crews from the Public Works Department were ready to be deployed to help with blocked storm drains, but they would not respond to homes with flooded basements.
By late afternoon, 26 residents - most of them homeless people picked up by city outreach workers - had sought refuge at shelters set up at four schools, officials said. Anticipating more crowds, the city opened a fifth shelter at a community center at 1400 E. Oliver St., and about 30 people showed up the first half-hour, officials said.
The winds brought down at least one vacant building in the city last night, in the 2400 block of Barclay St.
In , parts of the resort remained under a foot of water last night, including the inlet parking lot and bayside streets on the southern end of town. But with much of the state still waiting for the storm's worst, city officials were optimistic that they had made it through mostly unscathed.
Still, Mayor James N. Mathias Jr. said, "We're not out of the woods until we see what high tide is like in the morning."