Idaho’s Republican senators are urging Sen. Jon Tester to leave out a 4,500-acre roadless area on the Continental Divide near Yellowstone National Park that is one of the few places left where snowmobilers can climb high up the side of a mountain in eastern Idaho.

The Mount Jefferson area in the Centennial Range is a small but absolutely priceless piece of alpine heaven. I horse-packed through the Hellroaring Creek drainage in 1987.

Snow still hid in the shadows and the rocky cirque was bathed in wildflowers that surrounded its tiny lakes sitting at the top of the Mississippi watershed. Even though it was Montana, the easiest access is from Idaho, especially in the winter for snowmobilers.

Eastern Idaho has a lot of snowmobiling country but not much high mountain play area. These alpine areas are very popular for snowmobilers who run their big machines at full throttle to see how high they can go.

I rode with the editor of Snowmobile West Magazine that same year up to the alpine bowls of the Lionhead mountain range across the valley from Mount Jefferson. There he showed me what hill climbing was all about.

It wasn’t my cup of tea but I could see why he and other snowmobilers enjoy it. This alpine snowmobiling is a unique experience that snowmobilers will fight to protect.

For snow machine rental businesses in nearby Island Park, Mount Jefferson accounts for 90 percent of its business, said Fremont County commissioner Ronald Hurt.

“This is the last of it here,” he said.

There are economic interests on the other side of the debate as well says Mark Menlove, executive director of the Boise-based Winter Wildlands Alliance. Two Montana businesses offer backcountry skiing and huts around Mount Jefferson, he says in NewWest.com .

“A broad coalition of recreation and sportsmen’s groups and businesses from both states have endorsed the bill and specifically called for wilderness designation for Mount Jefferson,” Menlove wrote. “These groups and businesses are constituents too and their voices should be given consideration just like the Idaho snowmobile lobby.”

Sens. Mike Crapo and Jim Risch have urged Tester to remove Mount Jefferson but they aren’t opposing the legislation. They hope he will just satisfy the concerns of the snowmobilers, who say they had a deal when the Beaverhead-Deerlodge National Forest updated its plan .

The Senate Energy and Natural Resources public lands and forests subcommittee will hold a hearing Thursday on Testers’ Forest Jobs and Recreation Act. Hurt will be one of the people testifying so the issue will get an airing.

But as Menlove’s article shows environmentalists aren’t ready to just give it up. Overall, the value of the Centennials as a wildlife corridor between greater Yellowstone and the Salmon-Selway ecosystems is clearly the top ecological concern.

But the zoning issue between motorized and quiet recreation is the defining issue of the debate as it stands.