A 30-foot swath of a Georgetown street slid into a construction pit last night, swallowed by a sinkhole along M Street that emergency crews worked overnight to reinforce and keep from growing, officials said.

Businesses and homes around the intersection of Bank and M streets NW were evacuated about 7 p.m. after the giant chunk of Bank Street disappeared into the sinkhole near a construction site. Emergency crews tried to determine whether outlying areas were in danger.

"It could be like dominoes, a landslide growing farther and farther outward. We're trying to analyze all the stress points and brace them," said Alan Etter, spokesman for the D.C. Fire and Emergency Medical Services Department.

Rescue crews found a major water leak at one of the seams of the sinkhole, but officials weren't sure whether the leak had caused the sinkhole or whether the landslide had broken a water pipe, Etter said. No one was injured.

The sinkhole formed on the edge of a giant, block-long pit, a construction project that eventually will be an underground parking garage and two levels of retail shops.

The site once housed restaurants including the Philadelphia Cheesesteak Factory and the Little Tavern. Last night's landslide took out a chain-link fence and the retaining wall along the eastern side of the construction site.

M Street businesses from Wisconsin Avenue to 34th Street NW -- hit in recent years by a series of manhole explosions -- were once again cordoned off from their customers and asked to turn off their power and water. Several homes near the sinkhole also lost the use of water and gas utilities, officials said.

Bob Olson could see the space that used to be Bank Street from the balcony of his Prospect Street home. He heard commotion and screaming, and then someone yelled: "Your life is not worth your car! Get out of there!'' It was someone trying to retrieve a car from a nearby parking garage while police were evacuating Bank Street, he said.

He and his wife, Elena, helped their daughter evacuate her townhouse on Bank Street, across from the sinkhole. "At first, I thought the war in Iraq had come here," Elena Olson said, looking over the giant construction pit, which now contains broken chunks of Bank Street.

Some Georgetown residents reacted to the landslide with exasperation, having endured recent power outages and street closures brought on by the massive Georgetown Project, a years-long overhaul of the area's underground utility systems.

"Not again," said a woman who tried to drive her Volvo station wagon to her Georgetown home but was turned back by police.

Bank is a steep, narrow, block-long street that drivers often use to get around heavy traffic on M Street. Officials said inbound traffic from Virginia should be unimpeded this morning, but they predicted that today's evening commute might be troublesome because the sinkhole could spread beneath the outbound lanes of M Street, said Bill Rice, a spokesman for the District's Department of Transportation.

The sinkhole formed on the edge of a construction pit, once the site of restaurants including the Philadelphia Cheesesteak Factory and the Little Tavern. It is to become an underground garage and two levels of retail shops.