Navigating Mt. Bachelor’s bustle of snowboarder packs, powder hounds and family pods, it’s easy to forget that human activity isn’t all that’s happening on this small slice of national forest.

Mount Bachelor is a volcano, inactive for millennia but still sending steam and gasses to the surface. The mountain is also part of an ecosystem, populated by a variety of critters.

It’s this Mt. Bachelor I met on a recent Saturday when I joined a new tour at the ski area called Ski/Ride with a Ranger.

Launched in December, it offers the chance to ride the chairlift and ski or snowboard on the mountain with a naturalist.

While I’ve been flying down this Fuji-shaped mountain now for the better part of a decade, I realized there’s plenty I’ve been missing.

Like the Cinder Cone, a perfect cone that often rewards those willing to hike with soft, fresh snow. That feature I’ve trudged up so often is actually a youngster in geologic terms. It burbled up about 5,000 years ago.

Then there is the life happening beneath the surface. Thousands of mouselike mammals called voles zip around under the snow, scurrying up and down the tree wells we humans steer around. They provide lunch for numerous creatures in the food chain.

The concept of the tour is to join U.S. Forest Service volunteers on a few groomed runs, making periodic stops to talk about the surrounding environment. The tour lasts about an hour and is free (see “If you go”). It’s a cooperative effort by Mt. Bachelor, the Deschutes National Forest and the Deschutes Forest Conservation Association, a nonprofit organization.

The three parties worked together to operate a ski with a ranger program a little more than a decade ago, said Terra Kemper, ski ranger coordinator with the Deschutes Forest Conservation Association. But staffing and funding changes resulted in it getting dropped.

Last season, Mt. Bachelor showed interest in bringing it back. So in addition to the popular snowshoe tours, the groups piloted a few downhill ski tours last March.

“It was a big hit,” Kemper said. “We had really great sessions in just those handful of offerings.”

I first took note of the tours after seeing a sandwich board at the West Village base just before the holidays. As a ski-loving science nerd, I couldn’t wait for my first opportunity to tag along.

Nearly a dozen people, both Central Oregon residents and out-of-towners, convened just beyond the top of the Pine Marten chairlift. Among them were volunteer rangers Steve Gorton and Laurie Heuermann, both of Bend. The duo are retired physicians who have trained to share tidbits about the flora, fauna and subterranean activity at the mountain.

I soon learned that between the stops and riding the chairlift, participants make just two runs over the course of an hour. I felt fortunate then that I had stuffed hand warmers into my mittens and would advise participants to wear an extra layer to stay warm on Bachelor’s less hospitable days.

We swooshed down a groomed, intermediate pitch to Old Skyliner, following the bit of orange flagging tape Heuermann had tied to her coat. Bachelor wasn’t at its foggiest, but the tape helped amid the falling snow.

We stopped along the edge of the run next to stately, old trees. There, Heuermann introduced us to the mountain’s other life.

She pointed out the drooping tops of Western hemlocks, an evolutionary adjustment so as not to break under the heavy Cascades snow. The lime-green bits clinging to the trees is often mistaken for moss but is in fact a lichen, which is a fungus and an algae growing together in a symbiotic relationship. The algae performs photosynthesis, producing the vivid green.

Just as interesting was Heuermann’s discussion of the Clark’s nutcracker, which gets its name from the Lewis and Clark expedition.

The bird’s food of choice is the whitebark pine nut. It collects more than it can eat at a time and buries caches of them in the forest about an inch into the soil.

The relationship works out well. The high-calorie nuts feed the Clark’s nutcracker. But the bird sometimes forgets where it hid caches, in essence, planting the seeds for new trees.

The next run focused on the geology and cultural history of the mountain. Fumaroles — volcanic holes in the Earth’s crust — dot the mountain venting steam and gases. And magma continues to gather in a chamber beneath South Sister, albeit slowly.

Different volunteers will lead the tour through the end of March, and Gorton said they change up their talks depending on the questions and interests of the group.

“You could do this multiple times,” he said, “and still learn something new.”

The tour made for an hour well spent. The next weekend, riding the lifts, I shared some of my new knowledge with friends who have long skied on the mountain.

It’s just the sort of response that Kemper is hoping for.

“I think it offers an opportunity for locals and visitors alike to get their eyes up from the snow, to realize that we’re in a really unique high alpine environment,” she said. “I think just having that awareness of what’s around you provides a little more connection and appreciation for the place.”

If you go

What: Ski/Ride with a Ranger

When: 2 p.m. Saturdays and Sundays through March 31. Lasts one hour.

Where: Mt. Bachelor Ski Area. Meet at the top of the Pine Marten chairlift, or just inside the Pine Marten Lodge on blustery days.

Difficulty: Intermediate skiing or snowboarding skills required.

Cost: Free, but lift ticket and equipment aren’t included. No reservations required.

Contact: www.mtbachelor .com/winter/services_activities/activities/snow shoeing or 541-383-4055