WASHINGTON (AP) – Flooding from a weekend of heavy rain shut down the Justice Department and other major federal buildings Monday, and created a nightmare for commuters with washed-out roads, mud blocking the Capital Beltway and delays on the area’s rail lines.

The Internal Revenue Service headquarters, the Commerce Department and the National Archives also were closed Monday morning because of flooding, and the National Gallery of Art was closed because of weather-related problems with its steam system.

District of Columbia officials urged everyone to avoid the downtown area.

“They need to give us time to make sure everything’s OK,” said Michelle Pourciau, the acting director of the D.C. Department of Transportation. “We know that more rain is coming … We’re trying to prepare for the additional rain as well.”

The storm dumped more than 7 inches of rain in 24 hours Sunday and Monday at the National Arboretum, and a flash flood watch was in effect for the region, with another 2 inches of rain expected Monday. Rain is in the forecast every day this week because of a stubborn low-pressure system off the coast, the National Weather Service said.

In the Washington suburbs, emergency crews had to use boats to rescue dozens of people trapped by flood water.

Firefighters in Chevy Chase, Md., rescued 30 people by boat from a recreation center late Sunday, said Capt. Oscar Garcia, a spokesman for the Montgomery County fire and rescue service. In Hyattsville, Md., crews took 69 people trapped in flooded homes to safety, said Mark Brady, of Prince George’s County fire and rescue.

The high water also shut down Amtrak and commuter rail lines into the capital. Limited service had resumed between Washington and Philadelphia Monday morning but trains were delayed. Even Metro subway service in the city was disrupted until noon because of high water on the electrified rails downtown, said Metro spokeswoman Lisa Farbstein.

“Riders should bring an umbrella and a bucket full of patience,” Farbstein said.

Drivers weren’t having much more luck.

Underpasses were flooded, and on the Capital Beltway, a mud slide piled five feet of debris on the roadway near Alexandria, Va., backing up traffic.

Maryland State Highway Administration spokesman David Buck said falling trees and flooding were expected to be problems all week.

“People need to build in a lot of extra time for the next several days,” he said. “It’s going to be a challenging week.”

At the National Archives _ home to the Declaration of Independence, Constitution and other historic documents _ researchers were told not to come in because the moat surrounding the building on Pennsylvania Avenue had flooded, spokesman Susan Cooper said. Outside the Archives, crews used fire hoses to pump water from the lower level to the city sewers.

Cooper said a preliminary assessment indicated all records held there were “safe and dry.”

Even President Bush got an up-close look at the damage _ a large elm tree fell on the White House’s front lawn overnight, blocking one of the roads.

On Maryland’s Eastern Shore, 10 to 12 inches of rain fell over the weekend in Federalsburg, washing out roads and flooding church basements. Mayor Betty Ballas declared an emergency Sunday for the town of 2,600 residents, 60 miles southeast of Baltimore near the Delaware line. There were no reports of deaths or serious injuries.

In northeastern Maryland near the Pennsylvania border, Harford County officials Monday issued a mandatory evacuation of cabins along the Broad Creek watershed as the creek began to overflow its banks. Another slide dumped 6 feet of mud on U.S. Route 29 in Silver Spring, Md., closing the six-lane highway for at least a half mile.

Route 307 in Maryland was completely washed out in a large section, down to the gravel, said Maryland State Police spokesman Russell Newell. The road will have to be completely rebuilt in order to be used again.

“It is quite a serious situation,” Newell said. “There’s a lot of roads that have been disabled due to heavy rains and flooding.”

In Seaford, Del., cars were floating in a Wal-Mart parking lot after heavy rain on Sunday. Amy Walls, a spokeswoman for the city, said between 10 and 15 people were evacuated from homes in an area known for flooding.

Thelma Gillespie said water was waist-high in the family room of her split-level home and three of her vehicles were submerged up to their roofs.

“It’s just a mess. I don’t know where to start,” Gillespie said. “All my furniture down here was new last year, and I don’t have flood insurance. I don’t know what we’re going to do.”