At first glance it looked like a typical Saturday aftrenoon at the ski resort. Dozens of enthusists were whizzing down the slopes, zig-zagging through the scene terrain, riding the tranquil chair lift back to the top to descend the run again.

But a second look revealed a startling difference. There was no snow.

And the thermometer was poised at 82 degress; these skiers were practicing the lively downhill sport had only in light summer clothing. They were out on the slopes enjoying one of America's newest sports - grass skiing.

By making skiing a year-round sport, grass skiing seems to be the answer to the skiers' and the resort owners prayers. They don't have to frantically monitor weather reports to find out about conditions, and there is no frenzied rush to get on the new poweder in the morning or to get in a few runs before the crowds arrive.

Grass skis fit on any size or style of ski boot. The contraptions are an amalgam of roller skates, skis and tank treads. They roll with a conveyor-like action to propel the skier down long, grassy slopes.

The skis are 25 inches long, weigh about 11 pounds can be cleaned with soapy water and lubricated with oil. They cost about $135 a pair. Grass skis can teach a speed of 50 miles per hour. There's a distinctive dackety-dack noise as the skier barreds down a hill.

Invented by a German skier, Joseph Kaiser, in the mid-1960s, grass skiing has been popular in Europe for more than a decade. The sport made its debet in America this summer at Bryce Resort in Bryce Mountain, Va.

Bryce ski school director Horst Locher, a member of West Germany's national grass ski team, brought several pairs of the miniature bulldozer-like skis to the United States two years ago, and they caught on so well with the resort's regular ski fanatics that Bryce purchased more than a hundred pairs for rental, reseeded one of its slopes and cleared it of rocks. It opened the grass-skiing season on Memorial Day and plans to continue it on weekends until the snow-skiing season begins, usually in mid-December.

"Grass skiing employs the same techniques as snow skiing with a slight twist," explained Lodger, who has been trying to popularize the sport with such stunts as doing it in New York's Central Park and taping a segment of To Tell the Truth. "Unlike snow skiing grass skiing does not permit any sick-lips. As a result all skiers must employ the carving technique of driving the knee into the hill to make a turn.

"Carving means precise turns, which is also the ultimate goal of the snow skier."

So grass skiing is an excellent way to improve snow-skiing technique, according to Locher, and also to conditon leg and foot muscles.

To get the feel of the grass skis, Locher recommends a professional lesson for beginner and experienced snow skier alike. But unlike snow skiing, where the novice may not be ready to tackle a slope alone on the first day out, a beginning grass skiier is usually ready to try a run after half an hour of instruction.

"Coming down the slope for the first time is a terrific feeling - sort of like sky diving," said Keith Parker, a 27-year-old insurance salesman from Silver Spring who said he's always wanted to try snow skiing but had been constantly foiled by poor weather conditions. "It's great fun, and with all my grass-skiing practice. I hope I'll be a good snow skier when winter comes."

Even experienced snow skiers admit that grass skiing requires practice to gain proficiency.

"Grass skis are like overgrown roller skates, and since there's no sliding action they take some getting used to," said 53-year-old Bill Nimmo, an air traffic controller form Vienna, Va., who has been snow skiing for seven years. "It's one of the best leg-conditioning exercises, and it keeps you in good shape - but the ground is a lot barder when you fall."

While grass doesn't have the cushioned / padded effect of snow when a skier tumbles, experienced grass skiers contend that the sport is actually safer.

"When you fall in snow skiing you're still attached to those long skis by a strap, and they can hit you in the head or fly back and break your arm or leg," said 17-year-old Bill Longsworth, who won second place in the National Grass Skiing Championship held at Bryce in July. "You may get bruised or scraped grass skiing, but you don't break bones the way you do in snow skiing."

Long pants and long-sleeved shirt or elbow and knee pads are recommended, and goggles are advised for competition. But in hot summer weather, pros like Locher has seen skiing only in shorts.