Downhill racers: as big-time skiing consolidates, new environmental problems arise.

The downhill ski industry, founded by enthusiasts who started ski areas because they loved skiing, was long ago transformed into a big business run by bottom-line managers. But in just two years, four companies that once owned only one or two areas each have gone on buying sprees that now give them 23 percent of North America's ski business, and 15 of the country's top 35 ski areas. To strengthen these new empires, these four companies alone have committed almost $1 billion to expanding slopes and trail systems, snowmaking facilities, and hotel and real estate development.

This consolidation and its attendant expansion of big ski areas poses significant financial risk for these companies - and significant environmental risks for the mountain regions in which these ski areas wish to expand. At the same time, some of these companies are adopting a less confrontational, more cooperative stance in their dealings with regulators and environmentalists. All of which poses new challenges for the activists and organizations who watchdog the industry.

"Lately I've found the industry much more open and forthright in their development proposals," says Chris Killian, who rides herd on Vermont's ski industry for the Vermont Natural Resources Council. "But the proposals are just as big and aggressive as they've ever been."

Most of the big proposals Killian sees come from Les Otten's American Skiing Company (ASC), which didn't exist five years ago but which now owns six of New England's largest ski areas, and in 1997 bought three large Western resorts. Like the other three surging ski corporations - Vancouver-based Intrawest (seven areas, both West and East), Colorado's Vail Resorts (six areas) and California's Booth Creek Ski Holdings (10 areas) - ASC is counting on major development both on mountain (snowmaking and trails) and off-mountain (big hotels and base villages) to attract more visitors. These expansions raise several environmental issues:

* Wildlife: Expansions of either trail systems or real estate development can fragment habitat vital to bears, mountain sheep and goats, elk, deer, mountain cats, moose, nesting songbirds, or other alpine or forest-dwelling wildlife. For instance, the Land and Water Fund of the Rockies recently appealed a Forest Service decision to allow a major expansion of the ski area at Vail, saying the expansion is compromising habitat critical to elk, mule deer and the Canada lynx, which is an endangered species in Colorado and at risk throughout the U.S. Such problems are only accelerated by the industry trend toward making ski areas "year-round destinations" that offer summer and fall vacations, putting more people on the mountains at times when animals most use them.

* Water quality and stream health: Water withdrawals from streams for snowmaking can devastate insect and fish populations; such withdrawals have been an almost constant source of dispute in New England over the last decade. In addition, runoff from real estate development or seepage from wastewater systems can send microbial, chemical and thermal pollution into streams, lakes or groundwater.

* Air pollution: More visitors equals more cars, which means more air pollution. In addition, the diesel engines that power snowmaking equipment in many resorts also emit pollutants that cause smog and acid rain. The diesel generators at Vermont's Killington Ski Area, for instance, have made that resort the single biggest stationary air polluter in the state.

* Balancing uses on public lands: Many ski areas are on national forest land. Since skiing is just one of several possible uses for such land, some expansions, such as those proposed at Booth Creek Ski Holding's Loon Mountain Resort in New Hampshire, have led to forest-policy debates over how to balance those uses.

* Development sprawl: Finally, ski area expansion can lead to strip development, "condo-sprawl," housing inflation and traffic congestion, posing economic, social and infrastructure problems. Development has been a major issue in recent disputes over expansions at Booth Creek's Loon Mountain in New Hampshire, at ASC's Sugarbush in Vermont, and the "ski corridor" along Interstate 70 west of Denver, where mountain resort real estate booms have displaced local workers and covered thousands of acres of formerly empty fiats and slopes.

Why are the ski giants friendlier these days? "It's probably enlightened self-interest," says Steve Saltonstall, a staff attorney for the Conservation Law Foundation, a New England environmental group that in the early 1990s tangled repeatedly with ski areas in lengthy legal battles.

Carl Spangler, vice-president of planning and regulatory affairs for ASC, says that both ASC and environmentalists are trying harder to cooperate. "The issues are the same," he says. "But it's a different philosophy. I think both the industry and the environmental groups no longer want to do business the way we did it in the 1980s, sharpshooting at each other in the regulatory process.

Spangler and others point to several recent agreements that have emerged from this kinder, gentler approach. Intrawest's Stratton Mountain in Vermont, for instance, has cooperated extensively with state wildlife biologists to protect black bear habitat, and ASC has changed its water withdrawal regimen to meet newly revised streamflow standards. ASC also recently made a land swap with the state of Vermont that preserved 2,500 acres of prime bear habitat that Killington, the state, and environmentalists had been fighting bitterly over for almost a decade.

Not every activist has found the going easier. As Ted Zukowski of the Land and Water Fund of the Rockies puts it, "At least with Vail, we're looking at a large corporation that doesn't seem to concern itself much with what people of Vail Valley or Colorado think."

Activists say they'll be extra-vigilant in the next few years, as the industry continues its expansion and consolidation. Right now the emerging skiing giants are flush with (borrowed) cash and excited about new projects and a rosy economy. But as observers within the industry, on Wall Street, and in green groups have noted, several winters of poor snow or a recession could put these debt-heavy companies in a less cooperative mood.

"Make no mistake, this is a big industry now," says Michael Kellett of Restore the North Woods, which has tussled with Loon Mountain Resort over its proposed expansion. "Money is the prime motivation. And when push comes to shove, they'll be driven by the bottom line." CONTACT: American Skiing Company, PO Box 450, Bethel, ME 04217/[phone]; Restore the North Woods, 23 Bradford Street, Concord, MA 01742-2971/[phone].