By Bill Saporito

(FORTUNE Magazine) – There's only one leading indicator in the ski industry: snow. And not the fake stuff made on the slopes. When real snow comes down, the skiers come up -- even if they're buried in recession. In the West, heavy snow allowed resorts such as Colorado's Aspen and Vail to open in early November, one week sooner than in 1990. With the prime part of the season still ahead, conditions are ripe for a record year. Says Pat Peeples, PR director for Vail Associates, owner of Colorado's Vail and Beaver Creek areas: ''Snow this year has been tremendous. We are very, very optimistic.'' Skier visits to Colorado areas rose by an estimated 25% through mid- December. At Snowbird in Utah, visits were up 9% through December 22. In recession-scarred Vermont, resort owners had their best Christmas week in three years, helped by a good cover of natural snow. Notes Tom Meyers, marketing director of the Vermont Ski Areas Association: ''Until this year it's been hard to differentiate between the economy and weather, because we've had such lousy weather.'' Business fell 11% last year, when nature provided snow for just seven days of skiing, leaving the rest to man, who commands a higher rate to make the flakes. Two New England ski areas went off the proverbial cliff. Magic closed and Ascutney is in Chapter 11. Recession is leaving some tracks this year. Vacationers aren't booking as far in advance. Instead, they try to make certain that conditions are optimal before departing. And they aren't staying as long. Five days is typical. Says Rusty Martin, marketing vice president at Snowbird: ''That's not unique to skiing. The seven-day vacation is not as prevalent as it used to be.''