On a balmy weekday afternoon, a handful of hikers had reached the “M” on Mount Sentinel. They kicked back on the stone-white letter and took in the valley views, hardly noticing the erosion going on at their feet.
The walls holding back the dirt below the “M” are giving way, and those with an eye on the mountain fear that without attention the landmark will slough downhill.
Marilyn Marler, a natural areas specialist with the University of Montana’s Division of Biological Sciences, said the problem isn’t poor construction. Rather, she blamed the erosion on gravity.
“Many people every day for many years have sat and climbed on those walls, which is why they’re there,” said Marler. “But they’re starting to lean downhill, and the silt is coming out from under the ‘M.' ”
Members of the Montana Conservation Corps will attempt to fix the problem this weekend, leading volunteers on a work party to replace the retaining walls and tamp down new backfill.
It won’t be easy work, but Bobby Grillo, regional supervisor for MCC, said his crew is up to the challenge as it gears up for a busy summer of trail work.
“The bulk of the work is to improve the retaining wall beneath the ‘M,’ because it’s sloughing off,” said Grillo. “It’s got to be close to 35 feet long. There’s an old fire road that puts you pretty close to there, and that’s where we’ll be staging the material.”
The white “M” on Mount Sentinel was first planted in 1908, when members of the Forestry Club cut a trail up the mountain. They carried stones up the trail and stacked them to make the 13th letter of the alphabet.
In 1912, a wooden “M” replaced the stone. When the wood blew away in 1915, it was replaced with a permanent stone letter, which remained until 1968, when crews laid the concrete “M” seen today.
While work takes place below the “M,” volunteers will help pull knapweed. Native plants will be sewn, including bluebunch wheatgrass and spring chickweed, among others.
For the Conservation Corps, the weekend work on Mount Sentinel marks the first major project of the season before they head out for the Clearwater, Nez Perce and Bitterroot national forests.
“Locally, we’ll be working on a project on Mount Jumbo — a reroute with the Missoula Mountain Bike Club,” Grillo said. “It’s a fall-line trail that’s gotten to be 8 to 10 feet wide. We’re working on a more sustainable trail, and we might add three-quarters of mile to what’s there.”
Grillo said crews also have planned forays into western Montana’s backcountry. The west-side canyons in the Bitterroot Valley are on the list, along with work on the Wise River Ranger District of the Beaverhead-Deerlodge National Forest.
This fall, Grillo said, the Conservation Corps will wrap up the season in the Rattlesnake Wilderness, where they’ll help Mountain Water Co. on dam maintenance.
“They do maintenance for all the wilderness dams,” he said. “They’re using us to camp up there, and do some maintenance with hand tools, as much as that’s possible.”
Volunteers interested in helping on Mount Sentinel will meet at the base of the “M” trail at 9 a.m. Saturday. Crews will be at the site until 2 p.m. Lunch will be provided.