Two to three inches of snow fell in many parts of the Washington metropolitan area last night before the year's fourth snowstorm began diminishing into minor flurries.

Accumulations were heaviest in the southern part of the area, in such locations as Prince William Country, Va., and the lower portion of Prince George's County, Md.

With only about an inch or two of snow on the ground in much of the northern suburbs and in the city itself, gaps in the clouds appeared overhead about 1:30 a.m. and the storm seemed almost over.

National Weather Service forecasters said that slippery streets and roads would be one of the storm's principal hazards.

Although highway maintenance crews were at work in growing strength last night, roads were described as increasingly slick as temperatures dropped. There were many reports of minor accidents and of disabled vehicles. d

Washington was only grazed last night by the northern edge of a major snow storm that swept toward the Atlantic Coast from the Midwest, where it had brought record levels of snow to parts of Missouri.

Virginia points well to the south of the Washington area were expected to get substantially greater amounts of snow. Four to six inches was reported last night in the Roanoke area, with snow still falling.

In the Tidewater region, where as much as 15 inches fell during Wednesday's record snowstorm, as much as four to six inches of new snow was expected from last night's storm.

In the Washington area snow fell in many locations throughout the afternoon, but there were few reports of measurable accumulations until after dark.

By early evening, grassy areas, car tops and tree branches in downtown Washington began wearing coats of white. Streets were either gray with slush or glittering black under a coat of melted snow.

By about midnight one to two inches of snow was reported on many District streets. About an inch of snow was measured in Montgomery County, two to three inches in northern Prince George's, and three to three and a half inches in southern Prince George's.

About three inches of snow was reported in Prince William County.

Trucks began spreading abrasives last night on the District's bridges, first to freeze, and planned to turn next to the city's major arterial routes.

In addition to the fact that the brunt of the storm was expected well south of the city, local highway departments' snowy evening task was eased by one more significant factor in the Washington snow equation: Today is Sunday and there will be no morning rush hour.