The worst storm of this record-breaking winter brought 50-mile-an-hour winds, snow flurries and near-zero temperatures to Washington last night, forcing the first widespread natural gas rationing in the history of the nation's capital.

The cold front swept in from Canada through the midwest, plunging temperatures here from an almost balmy 48 degrees in late afternoon to an expected low of near zero. As the strong winds threatened trees and buffeted the few pedestrians who ventured out, the combination of wind and cold sent the wind-chill factor to near 50 below zero.

As the temperatures dropped the Washington Gas Light Co. decided that the demand for gas would exceed the capacity of the pipelines to get it here, the company proposed the drastic rationing plan that may close offices, schools, factories and theaters.

The public utility regulating agencies for the Washington area ordered commercial and industrial customers to turn down their thermostats to the minimum temperature necessary to keep pipes from freezing - approximately 50 degrees.

The late afternoon rationing decision created widespread confusion and uncertainly, verging on panic among some residents who feared that their heat would be totally cut off.

The emergency rationing was ordered through Tuesday, or until the cold wave ends, and does not affect residences or many services and businessess classified as "essential" - a category that ranges from hotels and restaurants to police stations to sewage treatment plants.

"There's never been anything like it," a Washington Gas Light spokesman said.

While some area offices probably won't open Monday, most federal employees will not be affected by the curtailment, John Galuardi, regional administrator of the General Services Administration said. Most federal offices are heated by oil or electricity.

A spokeswoman for Arlington's public schools, most of which are heated by gas said: "We will take each day at a time." The spokeswoman added that there was not enough information to make any decisions, and there would be no announcement about possible school closings until Monday.

No local school system yesterday had definite plans for Monday: none was sure whether schools would be open, held in buildings heated by fuels other than gas, or closed.

In the District, Mayor Washington issued a statement urging the public to cooperate in the emergency. The city Office of Emergency Preparedness said it will be operating around the clock and said people needing assistance should call 629-5151.

Earlier in the day, before the gas curtailment was announced, Safeway announced that starting Monday its 164 stores in the region would close at 9 p.m. in response to President Carter's request for additional energy conservation.

Baltimore Gar & Electric Co, the major energy utility in the Baltimore area, said that supplies to about 3,000 industries would be cut off today to preserve supplies for its nearly 500,00 residential customers.

The curtailment, the company said, will last until further notice.Most industries said a weekend cut-off would have minimal effect, but a spokesman for General Motors said 5,000 workers could be laid off if the rationing extends into next week.

Washington Gas Light has 491,000 customers who use gas to heat their homes, a spokesman said. They have been urged by the company to set their thermostats to below 65 degrees during the day and below 55 degrees at night. They have also been asked to make less use of hot water and gas appliances.

"There's enough (natural gas) t serve the human needs requirements, but not much more than that," Washington Gas Ligh Co. vice president Donald J. Heim said during a hurriedly called emergency session of the D.C. Public Service Commission. "To that extent, we are all in it together," Heim added.

The gas curtailment measures appeared to be partly voluntary and partly mandatory. Heim said they will require "a good faith attempt" by the company's customers. Talking with reporters, Heim warned that if businesses and others affected by the curtailment fail to comply, Washington Gas Light any take further action against them to curb abuses. Asked whether gas service could be shut off to customers who violate the new order, Heim replied, "That's a possibility."

The gas cutback for the District was authorized, after only limited discussion, during a 25-minute mid-after-noon session of the D.C. Public Service Commission which met in a small, overheated office at its downtown headquarters. It was approved by the commission's chairperson Ruth Hankins Nesbitt and one commissioner, William R. Stratton. The commission's third member, H. Mason Neely, was not present.

According to Washington Gas Light Co. attorney Monte R. Edwards, the company had already received "verbal approval" for the curtailment measures from public service commissions in Virginia and West Virginia, which is served by a subsidiary of the company. He said similar acceptance was expected in Maryland.

In West Virginia, Edwards noted, the weather itself was a temporary obstacle to getting approval of the gas curtailment. The state capitol, where the state Public Service Commission is located, had been closed because of the winter crisis. Edwards said the commission's chairman was eventually found at home and approval was granted.

Company officials said they were relying on the news media to alert their customers to the natural gas curtailment. The cutbacks, officials said, are expected to continue at least until Tuesday morning, when they plan to "re-evalute" gas supplies. It is unclear whether the curtailment may be extended beyond Tuesday.

Under the emergency measures, nonessential commercial establishments are required either to stop using gas altogether or to cut back their use of gas to the "minimum level required to prevent irreparable injury to life or property." The businesses and other gas users would be permitted to use enough gas, for example, to prevent water pipes from freezing, officials said.

Gas service will continue, officials said, to homes and apartments, hospitals, day care centers, nursing homes, motels, restaurants, food processers, prisons, police and fire stations, water and sewage treatment plants, dormitories and other residence's at schools and colleges, and laboratories and communications agencies that have "critical temperature requirments."

The company said its move to curtail natural gas service was promted by similar cutbacks by its two gas suppliers, Columbia Gas Transmission Corp, and Transcontinental Gas Pipe-line Corp. The two suppliers notified Washington Gas Light of the emergency cuts yesterday morning, officials said.

According to a Washington Gas Light spokesperson, the gas that heats the Washington area comes from Texas, Oklahoma and Louisiana through pipelines 40 inches in diameter. Currently, she said, gas is being taken out of the pipelines faster than it can be put in at the source as the colder temperatures demand more fuel to maintain the same temperature.

The pipelines, the spokesperson said, are not designed to hold the amount of gas demanded by temperatures as low as those here recently. "If the temperature goes below what the system is designed to handle," the spokesperson said, "the pressure drops and pilot lights go off."

The pipelines, she said, are designed to handle "99 and 44/100ths of the weather that we experience in this area. Current temperatures make for a situation that is just a "freak accident," she said.

Washington Gas Light Co, officials repeatedly asserted yesterday that they were not asking their customers to close their businesses and offices. They were only ordering them to reduce their use of gas to minimum levels, they said. Company spokesman Charles Krautler said that Washington Gas Light Co. itself will set its thermostal at 50 degrees and, nevertheless, will remain open and fully staffed.

Washington Gas Light's curtailment came a day after the Virginia Corporation Commission ordered a cuttoff of natural gas to industries, some schools and other nonresidential users in the heavily populated eastern users in the heavily populated eastern section of the state. About 75 per cent of the state is now affected by the rationing

While Gov. Mills E. Godwin had said Thursday that the cutoffs could lead to layoffs of about 20,000 workers, some affected industries, including the 6,000 employee Allied Chemical Corp. in Hopewell, indicated they could continue production if the empergency was short-lived.

Maryland Gov. Marvin Mandel signed an emergency bill passed Thurday by the legislature that permits hard-pressed oystermen on the Eastern Shore to use dredging methods to get at oysters hidden under blocks of ice in the Chesapeake Bay region.

Dredging is usually forbidden to fishermen because it is feared oyster beds would be stripped rapidly under such circumstances.

The bay region has already been declared a disaster area by the federal government, after watermen suffered losses estimated at $20 million.

The Economic Affairs Committee of the Maryland Senate called on Mandel to use emergency powers to close some schools and businesss, and permit the use of fuels normally banned because they pollute the air.

Earlier in the day, Mandel said at a press conference that he does not anticipate needing to use the powers in the immediate future.

"If we have to we will," he said "There's no question about that."

Electric companies serving the Washington area said yesterday they expect no brown-outs or other problems that could affect residents whose homes are heated by electricity.

A spokesman for the Virginia Electric and Power Co. said "Vepco expects to meet the demand that may be placed on the system for electricity . . . however, the demand will depend on a number of factors such as how long the cold spell lasts."

The Potomac Electric Power Co. said that the company had kept on extra crews to take care of any repairs if there is damage to the system from the wind.

(Also contributing to this story were Washington Post Staff Writers Lynn Darling. Athelia Knight. Stephen J. Lynton. Lawrence Meyer, Vernon Thompson and Judith Valente.)