A new snowstorm and continued transit delays battered the Washington area yesterday, while the city was still reeling from its heaviest snowstorm in three years and from nightmarish traffic Wednesday made worse by the Metrorail and airliner disasters.

This morning's rush hour traffic was expected to flow relatively smoothly, however, as yesterday's snow, which added a little more than an inch to Wednesday's accumulations, ended about 7 or 8 p.m. over most of the area. Little or no snow was expected today on top of the six inches on the ground in many sections.

Meanwhile, the 14th Street bridge has been closed indefinitely in the wake of the plane crash. Metro's Orange and Blue lines will be disrupted at least until this evening between Federal Center SW and McPherson Square, while crews remove debris and repair rail lines damaged in Wednesday's derailment. Metro General Manager Richard Page said full service would be restored by this evening's rush hour.

The White House announced yesterday that a delayed-arrival and a "liberal leave" policy would be in effect today for federal employes. That means that in most cases government workers who are late because of the weather will not be charged for annual leave, and those who wish to take the day off may use their annual leave time without consulting their supervisors.

All area schools are closed today in observance of Martin Luther King Jr.'s birthday, except Arlington County, which is opening one hour late because of poor weather conditions, and Fairfax County, which plans to open if weather permits. Schools were closed yesterday, and nonessential federal and District employes were given the day off because of Wednesday's snowfall and transit problems.

Local government offices also will be closed today for the King observance in most jurisdictions, except Montgomery, Fairfax and Arlington, which said they might close anyway because of snow. Transit officials said the holiday will ease traffic somewhat, but they were predicting chaos if the snow persisted.

Hundreds of snowplows and sand- and salt-spreaders managed to make roads passable early yesterday for the shrunken workforce that was estimated at 30 to 40 percent of normal because of the release of federal, city and some private-sector workers. But wet sticky snow that accumulated rapidly in midafternoon made homeward commuting more difficult.

For the second straight day, the snowfall quickly began to outstrip the prediction of the National Weather Service.

"Weather is not an exact science," said National Weather Service spokesman Walter Green, a veteran of 29 years of military and civilian weather forecasting and observation. "We just have to go with the best information we have."

The new snowstorm had been expected before dawn yesterday, with heaviest accumulations by the morning rush hour. But no snow was reported during that time, and a new prediction called for a one-to-three-inch fall to begin in late morning.

Once the snow started in early afternoon, the weather service steadily increased its predictions, calling for up to five inches in Washington and eight inches in the suburbs, but then ultimately forecast before 9 p.m. that little additional snow was expected until Saturday.

At National Airport, officials closed the runways for an hour begining at 6:30 p.m. to clear away accumulated snow. There was at least one brief shutdown earlier in the day to spread sand.

Ridership on Metro trains and buses was reported to be light yesterday, similar to a Saturday or Sunday, but by 4 p.m. many downtown buses were full as those people who did report to work headed home. Constitution Avenue was particularly crowded with traffic diverted from the 14th Street bridge to the Memorial Bridge.

Metro rail operations functioned on an nonrush-hour basis, with some disruptions yesterday morning when Orange and Blue line passengers were forced off their trains briefly while temporary circuit repairs were under way at the train wreck site.

Metro added more buses than usual to its schedule yesterday, but they still were running between 10 and 20 minutes late in the city and 10 and 45 minutes late in the suburbs because of road conditions and confusion left over from the night before. Many bus drivers were caught in Wednesday night's massive traffic tieup and didn't return to their bus barns until hours after they were due, Metro officials said.

Meanwhile, horror stories continued to emerge yesterday from motorists stuck in Wednesday's massive traffic jams. A trip to Rockville took five hours, and one to Springfield four hours. Some commuters gave up and checked into downtown hotels and bars.

Citizens showed some of their best and worst during the traffic crunch. Pedestrians became traffic cops, helping to clear clogged intersections. Cabdrivers in some cases refused to take stranded passengers, or demanded double pay or more. One entrepreneur exploited the tie-up by hawking beer to frustrated commuters on the Key Bridge.

Conditions were particularly acute at National and Dulles airports, where thousands of commuters were stranded for lack of ground transportation. National was closed shortly after the airplane crash at 4 p.m. and hundreds of people were forced to remain at the airport because Metrorail service was out and taxicabs couldn't reach them because of blocked roads. About 200 stayed the night, according to an FAA spokesman.

"Every major form of transportation in and out of the airport was at a standstill. It was like a total wipeout," said Sam Kaplan, president of Airport Limo and Airport Dispatch, which handles ground transportation at National and Dulles. Taxicabs were mobbed, Kaplan said, and stranded passengers offered motorists up to $200 for a ride downtown.

After the crash, flights scheduled to arrive at National were diverted to Dulles, which did not have the ground transportation to handle all the arrivals. Passengers were forced to wait hours.

Not all the tales had an unhappy ending. A busload of passengers bound for West Springfield in Fairfax County passed an envelope and tipped their Metro driver about $15 for his two-hour struggle against the elements and traffic. Said Jim Luciano, a Department of Energy employe on that bus, "it was a phenomenal job; he was a real hero."

Seward Cross, traffic engineer for the D.C. Department of Transportation, said city officials believe the federal government's abrupt early release of 350,000 metropolitan area employes Wednesday afternoon created an unnecessary traffic crunch.

"We question the wisdom, overall, of an early dismissal," Cross said.