Snow. Without it, a ski area dies. And when you haven't had much for two years running, a 24- to 45-inch base with a packed powder surface is money in the bank--if your customers haven't found something else to do and somewhere else to do it while your slopes were bare.

Last year, even 4,100-foot Wildcat Mountain--which lies across this notch in the White Mountains from Mt. Washington with its celebrated harsh and snowy weather--had many of its trails closed during the critical Christmas-New Year's week. Like every other ski area in New England, Wildcat also lost what snow it had last year in a February thaw so thorough that fruit trees began to bud.

Today most of the ski operators are all smiles. Those who are not are unhappy because business has only been very good, not great as they had expected. At Wildcat, business manager Bill Fabrizio has to reach back to the record 1977 winter for comparisons. The crowds are coming again, at least in the northern areas.

The $18 a day a skier pays at Wildcat for an all-lifts ticket is only the tip of skiing's economic iceberg. The Mt. Washington Valley has about 6,000 beds at more than 80 inns, motels and other lodgings. With the snow, most of the beds were filled during the holiday week, according to Mike Hickey of the valley's chamber of commerce. Some of the better restaurants were booked solidly, too. Many cautious customers checked in detail before committing themselves to reservations this year after they came a year ago and found, as one operator put it, more "fast grass" than snow.

Curiously, the merchants did not do too badly last year. Once the skiers had come north from Boston, Providence and New York and discovered the skiing was poor to nonexistent, they still spent time and money in the shops of North Conway and other towns. Another year of poor snow and the crowds might simply have melted away.

Down in Concord, state officials are just as pleased as the ski operators and the merchants. Tourism accounts for about 30 percent of New Hampshire's economy, and the state's 7 percent tax on rooms and meals is a significant source of revenue, especially since there is neither an income tax nor a sales tax here.

The state even owns two large ski areas, at Cannon Mountain in Franconia Notch and Mt. Sunapee farther south. Last year Sunapee was closed during the holiday week and several of Cannon's trails were unskiable. In the season two years ago, the two areas had disastrously low receipts of $212,000. Last year that improved slightly to $367,000. This year the total was close to $1 million, according to George T. Gilman, New Hampshire commissioner of resources and economic development.

With the state legislature meeting in a special session to find ways to come up with about $50 million worth of spending cuts or tax increases to balance the state budget, the added revenue is doubly welcome.

With the experience of the last two years, more and more ski areas here, just like those much farther south in Virginia, Maryland and Pennsylvania, are putting in or expanding snow-making equipment. Black Mountain in Jackson, which lies between Pinkham Notch and North Conway, has no snow-making equipment at all, and last year it never opened. It has just been sold, and rumors are flying that snow-making equipment must be on the way.

At Attitash in the village of Bartlett, the third of the four major ski areas in the valley, $1.7 million was spent over the summer on its first snow-making machinery. Normally, Attitash is open about 100 days a season. Last year, relying totally on nature, it managed only 32 days. In contrast, during Christmas week, Attitash, which limits the number of skiers to hold down lift lines (and charges accordingly), sold out.

By no means all of the ski areas have done as well as Attitash and Wildcat. As the snow began falling early in December, the hopes of operators across New England for the season soared. Some have been disappointed.

Cranmore Mountain, the oldest of the commercial slopes in the Mt. Washington Valley, has had much less snow this year than Wildcat, which is about 1,500 feet higher, but with snow-making equipment all of its trails have been open. However, Cranmore manager Herbert Schneider isn't quite as happy as Fabrizio, saying the Cranmore crowds have been good but not great. His comment is echoed by a number of ski operators elsewhere in the state.

At some of the smaller ski areas to the south, such as Whaleback in Enfield, N.H., and Mt. Sunapee, the snow conditions were better than the holiday week turnout. The state is designing a $1.8 million snow-making system for Sunapee.

Surprisingly, none of the operators seemed to think the state of the national economy, which is deeply mired in recession, is having much effect on the willingness of skiers to pay $18 a day or more for a lift ticket, or to shell out more than $12 a day to rent boots, skis and poles--assuming they haven't plunked down several hundred dollars for their own set.

Cranmore's Schneider believes there simply are fewer skiers than there were a few years ago. Meanwhile, more and more downhill ski areas have opened or have expanded, and there has been a resurgence in cross-country skiing, for which equipment costs are far less and for which there may be no direct daily cost at all.

In Jackson, a ski-touring foundation maintains and grooms miles and miles of cross country trails and asks only a $4 "donation" for their use. Those trails have been heavily used this year. From an economic point of view, however, cross country skiers also have to have a place to stay and eat, and they, too, pay that 7 percent tax to the state.

Alpine or downhill skiing began in the eastern United States in the 1920s in Tuckerman's Ravine on Mt. Washington, of which there are magnificant views from the slopes at Wildcat. Skiing in Tuckerman's is no easy day of sitting on a chairlift and schussing down again. It has no lifts at all and the only charge is for the energy expended on a stiff, two-mile, 2,000 foot climb into the ravine from this notch, and the added climbs up the side of the bowl for each downhill run.

Tuckerman's and Wildcat, a particularly rugged mountain, both lie within the White Mountain National Forest. The Wildcat ski area is operated under a permit from the U.S. Forest Service. So its success matters directly, in a very tiny way, to the federal government, too.

Wildcat's operator is a private corporation that has had to delay expansion plans for lack of capital. The lack of snow the last two years contributed to the problem. For instance, February is normally the best month in terms of income, partly because it includes the Washington's Birthday week that is a school holiday throughout New England. Last year, that was the month that wasn't.

Now Wildcat is trying to sell long-term ski passes to raise money. For $3,000 you can buy a silver pass good for the term of the Forest Service permit, which runs through 1999, and for any extensions of the permit. For $5,000 you can get a gold pass that has the same term but can be transferred twice--sold or inherited, for example--over the next 19 years and provides other privileges as well. If Wildcat can sell 100 of each, as it hopes, the $800,000 will be part of the $1.3 million needed for a new chairlift and an expansion of the base lodge.

No one has ever tried to calculate the economic impact of a year, or a string of years, without much snow, as far as anyone at the Mt. Washington Valley Chamber of Commerce knows. But with the economies of New Hampshire and Vermont somewhat depressed compared with last year, their proceeds from taxes and other sources related to tourism are up strongly.

Last month the state of New Hampshire's take from liquor sales, the rooms and meals tax, sweepstakes tickets and business taxes was up an estimated 20 percent from 1980, commissioner Gilman says.

Across the Connecticut River in Vermont, which has a similar rooms and meals tax, payments last month were up 23 percent, and the sales tax take was up 21 percent.

Not everyone is happy about the snow that has produced this comparative windfall. There are those disappointed ski area managers who had hoped for even better times, and there are the state and town highway maintenance officials who have to clear the white stuff away. Unless it stops snowing soon--another foot or more fell in the area last week--the snow removal budgets will be far into the red this year.