There still is a lot of snow on area mountains, despite unseasonably high temperatures and heavy rains.

It is machine-made snow.

In Vermont, where snowmaking is only a backup to snowfalls, warm weather has wiped out several areas and severely curtailed skiing at others.

If the Mid-Atlantic region waited for natural snow, we wouldn't be skiing at all this year. Ski Liberty has had only seven inches of snow this season, and the seven inches of rain that fell this month would have wiped it out 12 times over. "In four years Wintergreen would have been open only one week if we depended on natural snow," said Wintergreen's manager, Uel Gardner.

Like the other Mid-Atlantic areas, Wintergreen makes snow every day, even when temperatures for snowmaking are marginal. Last week, local areas reported up to 12 feet. "We never report what we really have because no one would believe it," said Camelback's Marilyn Hertz.

This superabundance of machine-made snow is insurance against warm weather. "There's a thaw every year," said Camelback owner Jim Moore. "It's just that this year the January thaw came in February."

It couldn't have come at a better time. December and January were excellent snowmaking months, enabling ski areas to build bases early in the season for good Christmas skiing and to keep building to foil any thaw.

But snowmaking does not come cheap. At Hunter Mountain in New York, where skiing continues through April, energy costs for snowmaking are more than $500,000. At Ski Liberty, area manager Hans Geier estimates that snowmaking costs him $600 an hour, half of which is for energy. Camelback, where snowmaking costs almost as much, makes snow 1,200 hours a year.

There is no question that machine-made snow is different. The stuff Mother Nature sprinkles has more air and less water. It is more forgiving. "Natural snow has a bounce to it," said John Graf, ski school director at Vermont's Stratton Mountain. "On machine-made snow you have to use a little more edge. You need a sharper ski and you have to know how to use your edges."

But ski area managers prefer machine-made snow just because it is so much more dense. A foot of nature's crystals would melt in two days in this weather. The machine-made snow hangs on.

"When I make snow I put all the water in I can," said Gardner. "I don't make skiable snow, I make snow that will last. I make it skiable by my equipment."

Snowmaking is only half the art. The other half is snow grooming.At Hunter they have three $90,000 machines, each 20 feet long, that can turn hard pack into something almost as light as powder in record time.

It is snow grooming that extends the season by reclaiming the snow that has built up along the sides of the narrow trails and aerating it and pushing it back in the middle, and by shaving moguls, fluffing up the snow, and evening out the bare spots.

"I wish it would get cold enough to use the equipment," said Camelback's Moore. "When we put the vehicles out they sink into the snow and ruin the whole mountain."

The word from Accu-Weather, Inc., the weather-reporting system used by most of the ski areas, is that it will be colder tonight, and snowmaking weather will return by mid-week.

"We could last a week, maybe two, without a break in this thaw," said one area manager, "but I'll be much happier when it ends."