President Carter declared major portions of Maryland and Virginia as disaster areas yesterday, permitting an estimated 5.300 ice-plagued seafood industry workers to apply for unemployment benefits and low-interest loans.

The Federal Disaster Assistance Administration said that residents of 26 counties and 12 cities in Virginia and 15 counties and Baltimore in Maryland would be eligible for the aid.

Anyone who has been unable to work or whose jobs, such as those of seafood restaurant employees, distributors and packers have been adversely affected by the ice-locked waters of the Chesapeake Bay and its tributaries can seek the federal assistance, the relief agency said.

While some waterman expressed pleasure about the anticipated federal aid and Washingtoninans yesterday enjoyed their second straight day of 40-degree temperatures, the lingering cold spell continued to earn its claim as the creator of the worst winter in many years, at least on the East Coast.

Washington-area shoppers, apparently panicky about possible shortages of Florida citrus products because of the freezing temperatures there last week, have started a run in local supermarkets on cans of concentrated frozen orange juice.

"We're ordering double our normal stock," said one worker at the Lyon Village Giant Store in Arlington. "We just can't keep the stuff; I'm refilling orange juice three times a day."

Half of the Anacostia section of Southeast Washington including most of St. Elizabeths Hospital for the mentally ill, was left a bit colder from 4:20 p.m. when electricity was knocked out because of a mal-function at Potomac Electric Power Co.'s substation at 2416 Martin Luther King Ave. SE.

Although many icy patches on side-walk throughout the Washington area melted in the above-freesing temperatures, the presidential legs of Jimmy Carter were not immune from a near spill. But with his arms flailing at the nippy air, Carter caught his balance before falling victim to an icy White House pathway.

While the East Coast and the Washington area has had an unusual amount of snow and cold weather this January, such is not the case in the western half of the country.

Colorado Gov. Richard Lamm has asked the state legislature for $150,000 to finance a cloud'seeding operation to make it snow to cover the state's largely snowless resort ski slopes.

In San Francisco, a state of emergency was declared and the city's public utilities commission asked its two million water system users to reduce their water use by 10 per cent because of a record winter drought.

While many Washington-area residents left coats unbuttoned and hats and gloves off in the relative warmth yesterday, a return to subfreezing temperatures is expected today and through the weekend, according to the National Weather Service.

Forecaster Joh Quadros said that more snow is possible tonight, although he said he could no predict what accumulation there might be.

Cold Canadian air is expected to pass through the Washington area this afternoon, he said. Mid-day temperatures in the mid-day timeperatures in themid-30s are expected to plunge to the middle 20s. Over-night temperatures tonight are expected to reach the low teens in Washington and single-digit figures in the suburbs, Quadros said.

The disaster relief benefits made availble yesterday include unemployment compensation of up to $89 a week in Maryland and S103 per week in Virginia, according to John Coleman, a relief agency spokesman. Up to30-year loans from the Small Business Administration will be availble at an interest rate of 6 5/8 per cent, he said. The loans are for individuals or businesses whose property, such as boats and fishing gear, was damaged as a result of the ice. people with broken water pipes or those who were laid off because of fuel shortages are not eligible, Coleman said.

Arlington, Fairfax and Prince William counties and Alexandria in Virginia and Anne Arundel and Charles counties in Maryland were included in the disaster area because some watermen live in the Washington area even though they work on the Potomac and Cheaspeake.

Eligible persons can also apply to the Internal Revenue Service to get early tax refunds, Coleman said.

William R. Frankin, a Deale, Md., oysterman for seven years, said he has been out of work since Dec. 29 because of ice on the Chesapeake. He expressed delight at the possibility of getting financial relief.

"I don't know exactly what it's suppose to do, but I sure am going to go and get (assistance). If I can do it tomorrow. I'm going to go tomorrow" to apply for benefits. "There'll probably be a waiting line."

Franklin said he usually makes "a couple hundred (dollars) a week easy." catching oysters and crabs in a nearby creek that is now frozen. "If the weather's good, we do real good," meaning about $400 a week.

No ceiling was placed on the total amount of the available federal aid. The watermen can draw uemployment assistance for however many months the cold weather lasts. Coleman said.

The brief respite from the subfreezing temperatures has not thawed much of the ice on the Chesapeake where Coast Guard crewmen have been breaking ice off hundreds of buoys and navigational devices with hammers, chisels, baseball bats and shot-gun fire the Coast Guard said.

The run on frozen orange juice began last week after announcements that a freeze had destroyed a large portion of Florida's orange crop. At the Seven Corners Giant store Tuesday night, one shopper was spotted carting out about 30 cans of frozen orange juice.

Citrus fruit shortages are not expected to be so severe that produce stalls will be left bare, since food chains also has citrus suppliers in the Southwest and California. But price increases are projected for both fruit and juice.

"There's no question there will be some price increase on citrus fruit as early as next week, but certainly no big jump," a Grand Union spokesman said.

"The worst thing the public can do is start panicking and hoarding orange juice," the Grand Union spokesman said. "If they just buy normal amounts it will do a lot to help keep prices stable."

Price increases resulting from low temperatures are showing up more on Florida vegetables rather than citrus fruit, food chain spokesmen said.