The greatest snowstorm in more than half a century left the Washington area smothered under almost two feet of snow yesterday -- a magnificent white menace that virtually imprisoned the city and sent road crews battling to reopen streets for this morning's commuters.

A total of 18.7 inches of snow fell Sunday and early yesterday -- the greatest single snowfall since a 28-inch storm collapsed the roof of the Knickbocker Theater in January 1922. Wind-blown drifts piled up to three and four feet deep in the District and to six and seven feet in the suburbs, covering familiar landmarks in a white blanket.

The storm came on top of additional snow already on the ground, bringing the total accumulation to 23.6 inches.

The snow here was part of a huge storm system that swept up the East Coast yesterday, dumping crippling amounts of snow from North Carolina to New Jersey. The system churned out to sea late yesterday, and forecasters called for partly cloudy conditions today and a chance of still more precipitation -- either snow or rain -- tomorrow.

The near blizzard, its ferocity miscalculated by stunned forecasters, triggered mammoth disruptions. National, Dulles International and Baltimore-Washington International airports all were closed. Amtrak trains limped in hours late.

Metro abandoned city bus service early yesterday, and Metro trains never ran at all.

Hospitals were short staffed. Some were running low on food and other supplies. Cars were marooned, turning to shapeless white hulks on the streets. Police and other emergency vehicles could not answer some emergency calls, and had great difficulty answering others.

Food stores were jammed with customers stocking up. Looting of some liquor and grocery stores was reported in both Prince George's County and Northeast Washington. D.C. police had made five arrests by mid-afternoon.

There also were deaths. Arthur Kuhl, 54, assistant secretary of the Senate, collapsed and died while walking to work at the Capitol. Police found him lying in the snow at First Street and Constitution Avenue NE and tried in vain to revive him by artificial respiration.

Another man, identified by Capitol Hill Hospital as Nicholas Cladis, 60, of 619 M St. NE, was found dead in the snow near his home, apparently a heart atack victim.

A three-year old Palmer Park girl died in an early morning fire in her home. Prince George's County Fire Department officials said deep snow and extreme cold caused a 20-minute delay in efforts to bring the fire under control. But they said the child probably would have died anyway.

About the only good thing that could be said was the storm hit during the long George Washington's birthday weekend, easing traffic and roadclearing problems somewhat and giving road crews extra lead time to prepare for today's morning rush hour.

Most government offices in the District and Maryland and Virginia suburbs were closed for the holiday yesterday, but transportation officials had to call in hundreds of extra crew members to cope with the snow.

Maryland Gov. Harry Hughes authorized about 50 National Guard members with four-wheel drive vehicles to assist state police in emergencies. More than 2,000 Maryland state highway workers using 1,100 plows and other heavy equipment were deployed along principal routes.A major setback caused by the storm was the cancellation of the annual George Washington Birthday Sale that had been set yesterday by hundreds of retailers throughout the area. The Metropolitan Washington Board of Trade estimated losses in the millions of dollars and said many stores probably will attempt to hold sales later this week.

There also were touches of generosity and compassion generated by the storm.People helped push stranded cars out of the snow. Many nurses and other hospital employes hitchhiked or walked to work and many other people arrived at hospitals volunteering to help. One farmer at the American Agricultural Movement's encampment on the Mall drove a nurse to Georgetown University Hospital in his tractor.

Several other AAM farmers, in a unique agreement with D.C. Deputy Police Chief Robert Klotz, plowed parking lots with their tractors at the Washington Hospital Center and at the downtown Trailways bus terminal. Farmers also offered transportation for persons in emergencies.

On Larkin Lane, a snow-clogged residential sidestreet in Vienna, neighbors all shoveled a portion of the street so that each could get an automobile out to the main road.

Few cars moved on Connecticut Avenue, K Street and other main arteries in the city. They were filled instead with people, some on skis. They waved and cheered to each other good-naturedly.

"This looks like a scene from Alaska," said Anthony Williams, native of Sierra Leone studying at the University of the District of Columbia.

A massive snowball fight involving some 500 people erupted at Dupont Circle. It ended on a sour note, however, when a truck driver confronted the crowd, complaining that members of the crowd had smashed his windshield with snowballs loaded with stones or other weights. Police arrived and dispersed the crowd.

Despite heroic efforts by many employes to get to work, area hospitals were particularly hard hit by the storm.

"We hit bottom around 7 a.m. as far as staffing and getting resources," said Steve Haray, on-call administrator at Georgetown University Hospital, yesterday afternoon.

"Right now we're trying to keep things going. We sent about a dozen jeeps (driven by volunteers) out to bring nurses in. A lot of people have been here for 20 hours, and we're trying to bed them down and feed them."

Haray said about 100 Georgetown University student volunteers were working at the hospital in nonprofessional roles. He said the hospital had to borrow food from the university to get through the day.

Volunteers also were reported offering help at other hospitals including Capitol Hill and Arlington hospitals. "It's just great," said Aunette Shamus, nursing supervisor at Arlington "People just started appearing. They're serving trays, distributing linens, shoveling sidewalks."

At least two babies were born at Washington Hospital Center when their mothers "were going to other hospitals and didn't make it," said Hospital Center chief executive officer Richard Lowrey.

Police departments throughout the area reported holding officers for extra shifts because of delays by replacement officers getting into work.

Asst. D.C. Police Chief Robert Rabe said about 300 officers were on duty yesterday, the normal complement for a holiday or "skeleton" shift. He said they were using about 70 scout cars, all equipped with chains, many of them assigned to shopping centers to deter looting that occurred sporadically during the day.

Mayor Marion Barry was in Florida on vacation yesterday and could not be reached for comment.

Prince George's County police responded only to emergency calls and went on some calls in four-wheel-drive vehicles donated and driven by local residents.

In outlying areas of Loudoun and Prince Williams counties in Virginia, police and fire officials reported several families evacuated to nearby hotels.

In Alexandria, an ambulance carrying a cardiac patient to Alexandria Hospital became stranded. A second ambulance going to its rescue also became stranded, and hospital workers ended up carrying the victim through the snow to the hospital a block away. The patient was reported in satisfactory condition.

Farther afield, the Coast Guard freported ice from shore to shore in the upper Chesapeake Bay. At Ocean City, Md., police said shelf ice now extends a quarter to a half mile into the Atlantic.

Coast Guard Lt. Geoffrey Powers said the Coast Guard has issued restrictions for shipping in Chesapeake Bay north of the mouth of the Potomac River. Only steel-hulled ships with a minimum of 1,000 horsepower (or 1,500 horsepower for tugboats with barges) may go north of the Potomac, he said. A Coast Guard escort is required for ships in the Potomac and Wicomico rivers, he said.

Despite the ice, Powers said, ships are having little difficulty getting into Baltimore harbor. He estimated ice in the bay is 14 to 16 inches thick in sheltered areas near the shore and about 8 inches thick in the middle.

D.C. Police reported the Potomas River frozen all the way across at Washington but warned adventurers not to try to walk on it. "It's much too thin and dangerous," a harbor section officer said.

In addition to the snow, the Washington area has endured extremely cold conditions since early February. Since February 9, the thermometer has risen above the freezing mark of 32 degrees only twice -- for about five hours on Feb. 16 and again yesterday for about five hours. The temperature has dipped below 10 degrees on six of the last 11 days and not risen above 36 degrees in that time.

Normal high temperatures during the day at this time of year are in the mid-40s, and normal nighttime lows are in the upper 20s.

The 18.7 inches of snow from yesterday's storm brings the total accumulation for the month so far to 30.6 inches. The record total snowfall for any February is 35.6 inches recorded in 1899.

A National Weather Service spokesman described yesterday's storm as a "near-blizzard." To qualify as a full blizzard, he said, a storm must include sustained winds of 35 miles per hour or more and reduced visibility of a quarter mile or less caused by snowfall or blowing snow.

He said yesterday's storm easily met the reduced visibility criterion, but its winds reached only the 20 to 25 mile-per-hour range.

Yesterday's snow comes in the wake of two heavy snowfalls earlier this month -- 5.6 inches on Feb. 7 and another 5.6 inches on Feb. 12 -- and much of the earlier snow was still on the ground when yesterday's whopper came.

The Middle Atlantic States, already blanketed by a succession of snows in the past weeks, were left in virtual paralysis by the storm. In the illprepared South, the snow caused 13 deaths.

In southern New Jersey, snow accumulated in drifts of up to 15 feet, and Gov. Brendan Byrne declared a limited state of emergency. In Delaware, Gov. Pierre S. Du Pont IV also declared a state of emergency. Delaware was trying to struggle out from under 13 inches of snow which caused power cutoffs in the southern part of the state.