The president of the International Snowmobile Association, Ed Klim, lives — where else? — in snowy Michigan, which ranks as the No. 1 state for snowmobiling, with 381,157 machines registered there, and he has four snowmobiles from which to choose: Arctic Cat, Polaris, Yamaha and BRP, the big four in the business.

Klim said the days of mixing oil and gas, screaming two-cycle machines and back-wrenching pull cords have been replaced by a new generation of sleek, high-powered sleds. Much of the engineering is based on motorcycles.

The price of a snowmobile ranges from $5,500 to more than $10,000. They have quieter, cleaner four-stroke engines, heated seats and hand warmers, and outlets for cell phones and other gadgets. Some even come equipped with global positioning systems, a great feature for riders who prefer to explore deep woods.

The tracks — deeply grooved rubberized belts — are wider, more pliable and quieter, and metal skis have been replaced by space-age compounds.

High-tech snowmobile suits come with heating elements and helmets with just about every feature NASA could cook up.

Despite the creature comforts, worldwide snowmobile sales have been in a steady decline, according to Klim's association. Since 2001, snowmobile sales have declined from 208,297 units sold to 164,860 in 2006. In the U.S. in 2006, 91,670 units were sold. Worldwide sales peaked at 260,735 in 1997.

"The snow conditions have not been good," Klim said. "There's no snowmobiling if there's no snow."

A bright global spot: Sales have increased in Scandinavia.

Klim acknowledges a certain elitism among winter enthusiasts and their views of snowmobiles and those who enjoy them.

"They think the only way to enjoy the outdoors is their way or the highway," he said. "That's fine."

Conditions aside, the anti-snowmobile sentiment is pervasive, and not limited to certain segments of the Northeast, either.

Disputes erupt periodically in parks and other public areas over whether snowmobilers should have access. The West Yellowstone entrance at Yellowstone National Park bills itself as the "snowmobile capital of the world," but confusion about snowmobile use in the park caused by competing court rulings has put a crimp in businesses there in recent years. The temporary rules, in place through 2007, allow a maximum of 720 guided best-available-technology snowmobiles in the park each day, including a limited number through the east entrance; there were 6,050 snowmobilers counted in the park in December 2006.

In Idaho, snowmobilers are fighting a wilderness proposal on Mount Jefferson under which the U.S. Forest Service would close the area to motorized vehicles. Conservationists say the proposal would protect wildlife and bring in tourists looking for quiet recreation, but local businesses that depend on snowmobilers, along with U.S. Rep. Mike Simpson, R-Idaho, have asked the Forest Service to alter the plan so the snowmobilers can keep coming.

LEARNING TO CO-EXIST

Snowmobilers are under fire from other quarters as well. Slate, the online magazine, once called the sport "the most noxious of the lot" of winter pursuits. The typical snowmobiler, Slate wrote, "is a grunt from Michigan's Upper Peninsula, a man who pauses on 100-mile rides to hit a circuit of boozy 'pit stops' with names like the Hoop 'N Holler (an actual destination)."

Joan Livingston, a novelist and avid snowshoer and former cross-country skier, learned to co-exist with the men and women who prefer motorized sleds when she lived in western Massachusetts. She and her husband, Hank, discovered that the trails groomed for snowmobile use formed a great base for skiing or shoeing there.

"The trails are there, thanks to the good graces of local landowners who consent to let the local snowmobile club maintain them," she wrote in an e-mail. "At the end of the year, the Worthington Snowmobile Club has a dinner for the landowners in that town."

The club, she said, has a groomer that packs the snow in "a nice aisle through the woods." She added, "The trails give you a unique perspective on a town's innards, and I can see why the snowmobilers like zipping through these frontierlike parts."

Livingston, who now lives in northern New Mexico, where there is plenty of snowmobiling and other winter sports, recalls getting along just fine with her speedier neighbors back in New England. If she was on foot on a snowy trail, she'd just hop aside to let them by, and found that "unfailingly," they'd wave as they passed. The only drawback, she said, was "the smell of exhaust" left in their wake.

In my snowmobiling days, I had access to hundreds of acres of forest and field. Trails I carved with my sled would leave a packed surface that my wife, Mandana, would use to silently retrace my tracks. I occasionally would don the narrow skis to join her.

Owning a sled without immediate access to trails is a bit like owning a boat without a marina. Throughout destinations that typically receive a fair amount of snow in the winter, like Maine, upstate New York and the northern Midwest states such as Wisconsin and Michigan, enthusiasts can be seen on the highways hauling their machines on ramps to wilderness areas. These can run anywhere from $600 to several thousand dollars.

If you can haul your sleds, there are more than 225,000 miles of groomed trails throughout the U.S.

A LEARNING CURVE

For beginners, getting the hang of a snowmobile is a somewhat like riding a motorcycle or a horse. You lean into turns, look ahead to where you want to go rather than down at the skis, and stay alert to hazards — low tree limbs, fences hidden by deep snows.

In states where snowmobile use is high, deaths related to the machines' use routinely number in the double digits. Wisconsin, for instance, records an average 25 snowmobile deaths a year.

Klim recommends newcomers to snowmobiling "go with someone who's done it" rather than attempt a solo trip. He also advised contacting a local snowmobile association, such as the Worthington, Mass., group, to learn the ins and outs of the sport.

As for children, many states and provinces regulate the operation of snowmobiles by young people. The industry also offers mini versions of the powerful machines that top out at speeds of 7 or 8 mph, Klim said.