For mountain snowboarder Stephen Koch, a recent adventure may be a case of riding out of the skillet and into the fire.

Grand Teton National Park officials said Friday that they are investigating a video that purports to show Koch and three friends from Park City, Utah, using a snowmobile to cross Jackson Lake to ski and snowboard the Skillet Glacier on 12,605-foot Mount Moran.

Snowmobiling in the national park is strictly controlled and the only snowmachines allowed on the lake are those being used by fishermen, officials said.

The video, posted on several Web sites including YouTube, Teton Gravity Research, TetonAT and StephenKoch.com, lasts about 10 minutes and chronicles a climb and descent of the famous Teton landmark.

The video, which can be seen below, includes shots of the party zooming across Jackson Lake at sunrise, two skiers being towed behind a snowmobile that carries two others and a variety of ski gear.

The video shows a climb of the Skillet Glacier and a descent by the four-person party through deep powder. It then shows the team using the snowmobile to recross the lake, apparently to the plowed Teton Park Road near Signal Mountain Lodge.

On the return trip, the video shows the team’s snowmobile stalled by water seeping onto the top of the lake’s ice cover.

The expedition ends after sunset and some digging and pushing.

“Hey, right,” one voice on the video says, “we got to skin [ski] across the lake after all.”

The film concludes in a pub with glasses raised high.

Snowmobiling across the lake shortens the skiing component of an expedition to Moran by about six miles, one way. Fit skiers who could maintain a military pace of 3 mph might spend four or more hours on that part of the trip.

In a note on his Web site, Koch says the climb and descent were made Feb. 7 with Jim Holland, Dave Peck and Alex Stoy, all of Park City. His text makes no mention of a snowmobile.

He did not return a phone call Friday seeking comment.

While ski blogs were abuzz with a debate over why fishermen can use snowmobiles and skiers can’t, a park spokeswoman said law enforcement is investigating regardless of the nuances of the regulation.

Yellowstone and Grand Teton have been undergoing a decadelong struggle to fashion a winter-use plan managing snowmobile traffic, and the latest iteration allows the machines on Jackson Lake only for those going ice fishing.

Even that plan is being challenged in court by conservationists who would like to see snowmobiles banned from Yellowstone and Grand Teton national parks.

“We are investigating,” park spokeswoman Jackie Skaggs said Friday. “It’s not something to take lightly. If warranted, citations will be issued.”

The distinction between using snowmobiles to reach ice fishing spots and employing them for touring or backcountry access “has been hashed over time and time again,” Skaggs said.

Regulations say machines are “for the purpose of ice fishing only,” Skaggs said.

Rangers can and will check snowmobilers on the lake for fishing licenses and gear. They might patrol to ensure that parties are not using ice fishing as an excuse to access backcountry ski slopes, Skaggs said.

“It’s not for touring around the lake; it’s not for joy-riding around the lake,” she said of snowmobile access.

“Given the sensitivity of the winter use issue in the Greater Yellowstone Ecosystem, a blatant disregard for the established regulations by individuals, such as these climbers, just further complicates the process of getting to a final decision on appropriate and sustainable winter use activities in our national parks,” she said.