A thick new blanket of snow began covering the already ice-and snow-burdened streets and pavements of Washington yesterday as another February day of numbing cold brought the area its third major snowstorm of the month.

Although the snow fell late into the night and accumulations mounted steadily toward predicted levels of five to seven inches, it appeared that the city would be saved from another catastrophe on wheels this morning by the widespread observance of today as Washington's Birthday.

Schools, local and federal government offices and many private businesses as well are closed today in observance of the holiday.

Area jurisdictions declared snow emergency plans in effect, autos maneuvered unsteadily over slippery streets, police reported dozens of minor accidents and the National Weather Service urged motorists to stay home last night if at all possible

Meanwhile, transportation officials moved to clear the roads for those who could not or would not remain at home today.

"Even on Washington's Birthday, you have some rush hour (traffic) and a big shopping day, so you can't cross it off," said Gary Wendt, traffic operations chief for the D.C. Department of Transportation.

Wendt described the weather outlook as "pretty bad," and said city streets would be no place for pleasure driving today. But he predicted they would be "drivable."

At about 10 p.m. as snow depths reached four inches city road crews were switching from spreading abrasives to plowing.

Hampering efforts to clear the streets and roads was the subnormal cold, which caused ice and snow to resist the melting effects of salt and abrasives, Wendt said.

The same frigid temperatures were blamed for the stream of complaints reaching officials from citizens with broken water pipes and defective furnaces. D.C. fire officials estimated that they got about 90 such calls yesterday.

By late last night the mercury here had reached no higher than 15 degrees, three degrees below the previous record for the lowest high temperature for Feb. 18 in Washington weather annals. Yesterday's low reading of six degrees was three degrees above the record low set in 1903.

Yesterday's snowfall, which was expected to continue into this morning, comes on top of 11.9 inches already recorded here this month, and is expected to make this the snowiest February since 1967 when 19 inches was recorded.

Weather service forecasters said they expected temperatures to begin moderating slightly later today, with highs possibly approaching 35 to Tuesday.

The snow that began falling here yesterday afternoon was the product of a vast storm system which drove northward from Georgia through the Carolinas towards Pennsylvania and New York.

By late in the day, the storm brought up to 15 inches of snow to western North Carolina and eight inches at a spot as close as Culpeper, Va.

It was spawned, according to forecasters, by the contact between moist air surging northward from the Gulf of Mexico. and the frigid air from northern Canada that has inflicted subnormal temperatures for days on most of the eastern United States.

Yesterday's subfreezing chill brought a mixture of holiday pleasure and wintry chargrin for many Washingtonians. There were an abundance of ice skaters and even a few joggers. There were last-ditch shopping trips, frigid waits for bus rides, cars that had to be jump-started and leaky roofs.

There were families who spent a warm Sunday at home and other residents who had to work outdoors in yesterday's cold, frequently outfitted in several layers of clothing and still describing themselves as chilled to the bone.

"I haven't been able to move my car since Monday," said Lynn Boor, an Arlington resident, as she stood beside two carts loaded with groceries at a Grand Union supermarket off Rte. 50. "I finally got a friend to bring me here. But I don't know if we can get home in time to miss getting caught in it again." Snow started falling at mid-afternoon.

While yesterday offered some families a chance to stock up for today's holiday, others viewed it as an opportunity to escape after having been cooped up at home for several days.

"People have been coming in here today by the droves," said Paula Seymour, a security officer at a Woodward/Lothrop department store in Seven Corners. "It's not the sales.They're telling me they're frustrated because they've been shut in all week."

Like many local roofers, John Lafranchise has, he says, received dozens of telephone calls at his Brentwood office from homeowners who complain about water seepage in roofs and walls.

"The problem is that when ice clogs up gutters and pipes on the roof, there's nowhere for melting water to go except where gravity'll take it," Lafranchise said. "And there's really nothing that can be done about the problem until the weather warms."

For many, yesterday's weather was a small test of endurance. "It's rough," said W. J. Buchanan, as he waited for a bus on Georgia Avenue NW. "I/'m freezing, man -- cold feet," said Alexander Winters, a gasoline station attendant who was dressed in two pairs of paints, four pairs of socks, three shirts, a hooded jacket and a green wool cap.

At Bethesda Fire Squad No. 25, Pvt. K. E. Lecompte described a ride on a ladder truck. "Our cheeks feel like they'll fall off when the wind is up," he said.

For some, yesterday's weather, despite its human discomforts, was also a marvel of nature. In Ocean City, Md., the Atlantic Ocean was reported to appear frozen "as far as the eye could see" -- for the first time in recent memory, according to several observers.

"There's absolutely no surf and no waves," said Walter Patterson, an Ocean City boardwalk resident. "There's nothing moving at all."