Southern Maryland bore the heaviest burden of the surprise snow storm that pummeled the Washington area Tuesday, with up to 18 inches of snow blanketing the area.

Areas nearest the Chesapeake Bay were hardest hit by the storm, which churned up the coast from the Carolinas. In Hollywood, in St. Mary's County, 16 1/2 inches of snow had fallen as of 5 a.m. yesterday morning, according to Floyd Abell, a widely consulted local amateur meteorologist.

While conditions had improved significantly by Wednesday morning, roads were treacherous on Tuesday, with heavy snow falling and wind gusting to more than 30 mph, driving drifts of snow across just-plowed roads. Across the area, wind-whipped snow slashed visibility.

Calvert County announced at midday yesterday that its schools would be closed today, for a third straight day. Charles and St. Mary's counties had not decided as of midday yesterday whether to close their schools today. With yesterday's school closings, the three systems had used three of the four snow days that are built into the school calendar. Once they miss more than four days, administrators must consider whether to schedule makeup time.

The miserable weather drove most people indoors Tuesday--where they stayed. "It's real quiet," Paul Wible, director of emergency operations for St. Mary's County, said as the snow fell Tuesday. "Everything is closed. County government is shut down. It's real quiet. Thank goodness."

In Calvert County, snowplows hit the streets at midnight Monday and worked straight through Tuesday. But crews could not keep roads cleared, said Bob Short, public safety director.

"They can't get ahead of it because it's still snowing and blowing," Short said during the storm.

Winds began whipping across the county at midday Tuesday, raising the prospect of road-blocking drifts, Short said. "It's going to cause us a lot of problems," he said.

Indeed, by early Tuesday afternoon, even snowplow operators were having trouble navigating the roads--one plow became immobilized after sliding off Route 231 in Calvert County. Winds were so strong that some stretches of roadway were almost completely free of snow, while drifts close to two feet high were reported elsewhere.

Conditions in St. Mary's County, already bad Tuesday morning, deteriorated markedly during the afternoon, with the main roads disappearing under drifts. The white roadways and white horizon converged, making navigation difficult.

On some of the winding roads, only a single lane had been plowed, and the few drivers out drove cautiously, unsure what might lie ahead.

A train of plows moved down Route 235 in St. Mary's County around 2 p.m. Tuesday, but the pavement they scraped was covered again within minutes as the snow picked up intensity as the afternoon wore on and the winds grew.

A few were out braving the conditions.

Unexpectedly emerging from the near white-out conditions in Southern Maryland, Jim Alexander rode his trusty mare, Lady Alexander, down the middle of Route 6 in Charles County around noon Tuesday.

With his leather chaps, leather duster and straw cowboy hat coated with ice, Alexander looked like a traveler from the past as he rode through Zekiah Swamp east of Dentsville. He was in the midst of a 12-mile ride from Charlotte Hall in St. Mary's County to Bel Alton, along the Potomac River in Charles County, where he intended to surprise friends. He had started around 9:30 a.m. and figured he was about halfway there.

"Quite a few people have stopped and asked if I'm okay," said Alexander, 40. "I've said, 'You're asking me? You're the one that's going to get stuck, not me.' "

Indeed, Lady Alexander was experiencing few problems staying out of drifts and contentedly ate snow while her rider paused to talk.

Alexander, a drywall installer, had ice clinging to his eyebrows but insisted he was having a fine time. "She probably ain't," he said, nodding at the horse. "But I am."

Alexander, who lives on a farm near Charlotte Hall, said he often rides in the snow but added, "I haven't ridden in a big storm like this before."

Mary Hertzer, 19, an Amish schoolteacher, rode with two companions in a horse-drawn black buggy to Moeller's Bait and Tackle, at the junction of Routes 5 and 6 in St. Mary's County. "It's beautiful out here," said Hertzer, who went for the ride after the school where she teaches closed early for the day. The group picked up microwaved pizza and soft drinks from the store before continuing on their way.

Cliff Stathers, who runs a heating and cooling business, was cruising Route 235 in his red GMC pickup, which he had used to pull several cars out of ditches. "It gives me an excuse to go play out in the snow," he said.

"They're plowing like crazy, but they just can't keep up with it," he said of the road conditions Tuesday afternoon.

But Stathers said he welcomed the heavy accumulation. "If it's going to snow, let it snow, instead of just making a mess," he said.

At Hill's Halfway House, a restaurant and bar in Mechanicsville in St. Mary's County, a decent crowd had gathered by 1 p.m., eating hot sandwiches, drinking Coors Light and playing keno.

Debbie Quade, who works as a Giant checkout clerk, said a foot of snow on the ground was no reason not to stop by her regular hangout. "Can't let a day go by without playing," said Quade, who had already won $100.

The Halfway House was one of the few establishments open in the area. But owner Bill Hill decided to close at 3:30 p.m. so his employees would not have to drive home in the dark.

Some people welcomed the storm.

"We're doing wonderful out here," said Mary Gooding between serving customers Tuesday at the Nanjemoy General Store in a remote section of western Charles County. "We love this stuff!

"It's extremely busy. We're the only store within an eight-mile radius."

Gooding's customers were snapping up bread, milk and toilet paper--as well as supplies from the side of the store that sells wine and liquor. To Gooding, it appeared residents were preparing for a siege of several days.

"It's really not that bad. I'm from Wisconsin, so this is nothing," Gooding said. "They panic down here. It cracks me up."

Jean Claude Baptiste, a 35-year-old Calvert County resident who originally hails from Chicago, also was unfazed by the storm. He went out shopping, buying a new battery for his truck.

"I love it, man," Baptiste said. "This is normal for Chicago."

Doug Hawk said he loved the snow, too. He should--Hawk was out making some extra money driving a snowplow in Calvert County.

"My only regret plowing is I'm not home playing with my kids," Hawk said.

Other Calvert County residents were ignoring the storm and taking advantage of empty stores.

"You can get the best movies," said 62-year-old Mark Shoup, who took the opportunity to rent some videos he had been unable to get before.

At the St. Inigoes Market on Route 5 south of Leonardtown in St. Mary's County, the storm just about halted the normal lunch trade, said Helen Harris, a clerk.

Some customers had walked in rather than brave roads that remained slick despite repeated passes by the snowplows, Harris said. Trade remained sparse through midday Tuesday, with customers mainly limited to snowplow crews stopping in for some food. "We're not getting the normal run yet," Harris said.

Police throughout Southern Maryland reported light traffic and few accidents. Law enforcement officials said it appeared most residents had taken the day off and simply stayed home.

"It's messy and nasty out, but it's not as bad as you think. . . . It's been very calm. It's surprising," said 1st Sgt. Randolph Stephens Jr. of the Maryland State Police barracks in Waldorf.

Staff writers Todd Shields and Annie Gowen contributed to this report.

CAPTION: Anita Austin struggles to steer a shopping cart in the slush Tuesday outside the Super Fresh Store in Waldorf.

CAPTION: Jim Alexander rides Lady Alexander through the snow Tuesday on Route 6 near Zekiah Swamp in Charles County on his way to visit friends in the Bel Alton area.