The thin, slushy blanket of white began melting early yesterday under a sparkly sun, a reminder that winter had not quite arrived. Sledders had to move fast to find a worthy slope. But it was just enough snow at just the right time to set hundreds of thousands of Washington-area students free from school for an accidental three-day weekend.

Williamsburg Middle School students Sara Brigagliano, 12, Ella Richardson, 11, and Heather Smolinski, 11, did their homework Thursday night, just in case. But when news came that the day was theirs, they sprang into action. First, they went to Sara's house and did gymnastics in the basement. Then they asked her mother to take them to Tysons Corner Center for burgers and browsing. Afterward, the plan was to go sledding at Ella's and then hot-tubbing at Heather's.

Problem was, the snow might melt by afternoon. Shouldn't they have gone sledding first?

"We thought of that," Sara said. "But we couldn't come to the mall with all, like, snow stuff on. That would have been a problem."

Not that Jack Sanders minded. The 9-year-old third-grader from Bethesda, released from classes at Woods Academy, romped on a hillside with friends first thing in the morning, had hot chocolate and went to Westfield Shoppingtown Montgomery with his mother in the afternoon to catch a new movie about an exceptionally long, intense and magical winter.

Before he saw "The Chronicles of Narnia: The Lion, the Witch and the Wardrobe," Jack offered this assessment of the weather: "It was good snowball snow. Because of the ice. It would stick together and wouldn't fall apart."

Schoolchildren took a straightforward view of their one-day liberation -- "Great!" blurted Christopher Norman Jr., a sixth-grader walking with his family through the Bethesda mall -- but meteorologists had a more nuanced appraisal of the storm. It dumped 2 to 4 inches of snow and other forms of precipitation late Thursday and early yesterday in District and surrounding areas .

"Snow, sleet, freezing rain and liquid rain, all within a small area," said Steve Rogowski of the National Weather Service in Sterling. "That's a very complicated system."

But not too complicated to measure: Spotters told the weather service that 5 inches of snow fell in Frederick, 3.5 in Colesville and in Woodbridge, 3 in Vienna, 2.2 in Falls Church and 1.6 at Reagan National Airport. Ice readings included 0.18 inches in Colesville and 0.1 inches in Annapolis.

With temperatures hovering near freezing much of the day, the snow was wet and prone to melt. The most fell between 2 and 6 a.m. "It was almost a worst-case thing, right before the morning rush hour," Rogowski said.

The weekend forecast calls for sunny or partly cloudy skies and continued chilly conditions. No snow is immediately in sight.

By 5 a.m. yesterday, there was a virtual consensus among area school officials to shut down.

"The roads were a mess at that hour," said Montgomery County schools spokesman Brian K. Edwards. "Student safety trumps everything."

Officials of D.C. public schools and school systems in the Maryland and Virginia suburbs came to the same conclusion. Many private schools, which track public school snow decisions, followed suit.

Utility officials reported few storm-related power outages. Roads seemed to be cleared fairly quickly. So were local airport runways. But the storm disrupted service for many airline passengers throughout the East Coast, including some at Reagan National and Dulles International airports, said Courtney Prebich of the Metropolitan Washington Airports Authority.

In Alexandria, much of the snow had melted to a soggy mush by about 9 a.m. Most streets were clear. So clear, in fact, that on DeWitt Avenue in the Del Ray neighborhood, one would-be snow-shoveler in sunglasses and yellow galoshes rode his bike to prospective clients, his red shovel jauntily resting on his shoulder.

Still, schools were closed. And that meant James Green and his wife had the typical morning discussion: whose job was more important, and who had to stay home with the kids, Brandon, 9 and Malcolm, 11.

"I didn't understand it," Green said of the decision to close schools with scant snow on the ground. "It ain't even worth it."

His wife won.

"I didn't really care," he said, smiling. "It meant I got to hang out with the boys."

The storm, flowing from the Ohio Valley, merged northeast of Washington with another that came from the Carolina coast. The combined system then moved up the Atlantic seaboard.

In the afternoon, Boston was hit by what officials called a "micro-blizzard" or "thunder snow," including a sudden whiteout with flashes of lightning.

New Yorkers woke to puffy snow, fluttering gently in the wind. Then rain and sleet fell on the six inches of accumulated snow. Before most folks had a chance to shovel their sidewalks and stairways, the city was covered in a messy, wet slosh.

By late afternoon, the sun had peeked out and a light wind sent mini-snowbombs hurtling off skyscrapers, annoying carriage-pulling horses and startling several pedestrians. "It looks good for the first half-hour," said Linda Swain 31, as she pulled cappuccinos at a midtown coffee shop. "Then it . . . gets all over your clothes and shoes."

Staff writers Lori Aratani, Tara Bahrampour, David A. Fahrenthold, Michelle Garcia, Hamil R. Harris, V. Dion Haynes, Carol Morello, William Wan, Martin Weil and Eric Weiss contributed. Garcia reported from New York, nd Fahrenthold reported from Boston.

Kristen Greenwaldt, 9, walks up the hill at St. Stevens Drive and Hampshire Circle in Waldorf to slide back down with family and friends. Ed Albers, with his children Corrine, 8, and Kyle, 10, grabs his dog Koa as he tries to maintain an upright position while sliding down a popular sledding hill off Truro Parish Drive in Broadlands. Walking along Wolfe Street in Alexandria might have been easier than scraping snow off vehicles.