The disruption extended to rail travel. In Washington, parts of which received about 7 inches of rain over 24 hours, Metro service disruptions sent hundreds of morning rush hour commuters into the streets to catch shuttle buses or walk to their offices on a muggy, overcast morning.
MARC train service on the Camden and Brunswick lines was canceled for both the morning and evening commutes yesterday because of downed trees, flooding, signal problems and stopped freight trains on the CSX-owned tracks. Service on the Amtrak-owned Penn line operated on a modified schedule.
The Maryland Transit Administration said MARC service was expected to be back to normal today - subject to any serious impact from more heavy rains during the night.
According to Cheryl Stewart, a spokeswoman for Baltimore-Washington International Thurgood Marshall Airport, there were scattered delays and cancellations of incoming flights yesterday into the evening. And passengers arriving early yesterday encountered hours-long delays finding ground transportation.
The flooding problems were compounded by a large number of trees falling across roads and railroad tracks. In Washington, where several government agencies closed yesterday, a 100-year-old elm fell on the White House lawn during the storm.
"The ground is so saturated now it's not going to take much wind" to knock over a tree, Buck said. "It just uproots it."
Falling trees were also a factor in many of the power outages that affected tens of thousands of Marylanders. Linda J. Foy, a spokeswoman for BGE, said about 69,000 customers had been affected by outages as of yesterday afternoon - though most of them had already had service restored. She said the utility expects the problems to continue at least through tomorrow.
Similar problems were affecting phones. Christy Reap, a spokeswoman for Verizon, said calls reporting service problems were running at about double normal levels.
The National Weather Service's highest 24-hour precipitation reading in Maryland as of yesterday morning came in Hyattsville, where boats had to be used to evacuate almost 70 residents over the weekend. More than 10 inches of rain were recorded in that Prince George's County town.
In Dorchester County, farmer Jimmy Goslee said he has never seen any weather like that of the past few days. "My rain gauge only measures up to 6 inches, and it ran over and kept running over," he said. "I'd guess we had 9 or 10 inches."
In Galestown, the flooding left a 30-foot-wide hole in a road. Town Councilman James Sullivan stood at the edge of the crater, watching as untold gallons of water surged from an old mill pond and through the hole.
There's now only one way in and one way out of the hamlet of 60 houses and 100 residents - adding 30 minutes of travel for Sullivan and other commuters.
"We are definitely cut off, and we're going to stay cut off, from the way things look," he said.
Reports of heavy flooding sent some mayors and town officials who had been attending this week's Maryland Municipal League convention in Ocean City back home.
Adam Ortiz, mayor of Edmonston in Prince George's County, left the gathering along with most members of that town's council, said Tracy Farrish, the only council member to remain.
"The town is in a flood zone, and the pumping station wasn't working properly," she said.
Throughout the region, government officials urged motorists to avoid driving into moving water. In Anne Arundel County, officials reported seven water rescues involving vehicles since Sunday - one a near-drowning.
Problems weren't limited to flooding. Lightning struck a $1.2 million Cooksville home Sunday evening, starting an attic fire that quickly engulfed the 5,300-square-foot house.
The home is in a rural part of western Howard County that lacks municipal water or sewer systems.
William Mould, a spokesman for the Howard County fire and rescue department, said firefighters from Howard, Montgomery and Carroll counties "intermittently" ran out of water but were able to prevent the fire from spreading to nearby homes. No one was injured.
In Harford County, the storm prompted a voluntary evacuation of weekend cabins beside Broad Creek in the Darlington area.
Most of the owners of the several hundred cabins had already left for the start of the workweek, said Darlington Volunteer Fire Company Chief Sam Sauers. When firefighters knocked on doors about 7 a.m. to warn residents about the high water, they found about a dozen people preparing to leave, Sauers said.
"They were already packed up when we arrived," he said. "They know what can happen."
At the nearby Broad Creek Memorial Scout Reservation, the lake reached 4 feet above its high-water mark about 6:30 a.m. yesterday, said Ranger Dave Weissert. The Cub Scouts spending the week at the camp were playing rainy-day games and singing songs to make the best of the soggy weather.
"We're drying a lot of socks and sleeping bags," said Weissert. "But we're still having fun."
Sun reporters Chris Guy, Laura Barnhardt, Melissa Harris, John Woestendiek, Nia-Malika Henderson, Beth Hughes, Julie Hirschfeld Davis and Tyrone Richardson contributed to this article.