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From rock slides to trails, ongoing earthquakes are changing the shape of the Sawtooths

Posted at 9:30 AM, Oct 20, 2020
and last updated 2020-10-20 11:30:37-04

This article was written by Nicole Blanchard of the Idaho Statesman.

Six months after a major earthquake rattled Idaho, the rumbling has continued with a quake shaking near Stanley as recently as Monday morning. Since March 31, the earthquakes have intrigued scientists and, in some cases, reshaped the landscape of the Sawtooth mountains near their epicenter.

The initial magnitude-6.5 quake and its aftershocks caused multiple avalanches in the Sawtooths, but many of the effects were masked by snow. As the weather warmed — and as strong quakes continued — more ramifications came to light: the ‘liquefaction’ of a popular beach at Stanley Lake, toppled rock climbing destinations, structural damage to lava tubes at Craters of the Moon National Monument and Preserve and debris strewn over trails.

“The earthquakes and their effects on the Sawtooth skyline have been an interesting exclamation mark on an already surreal year,” said Ed Cannady, former backcountry manager for the Sawtooth National Recreation Area, in an email.

He noted the loss of the Arrowhead and the Finger of Fate, two distinct peaks favored by rock climbers, in the March 31 earthquake, as well as Baron Spire, which collapsed in August. Video of Baron Spire crumbling and triggering a rockslide went viral online.

“As a climber, I can tell you it’s changed a decent amount of climbing in the Sawtooths,” Blake Bolton wrote in a Facebook comment on the Idaho Hiking and Backpacking page. “… Another feature known as the Coffin is gone along with the Arrowhead, and the summit pitch on Warbonnet has changed as well. I’m sure there are other changes but that’s the extent of what I’ve seen so far.”

Cannady said some of the changes have gone unnoticed because they didn’t affect any of the prominent peaks of the jagged Sawtooths.

“There have been many other changes that were much less notable because they didn’t change the appearance of the skyline,” Cannady said. “Several walls have had partial shears, such as the towers above Hansen Lakes, the east face of Grand Mogul, Peak 9565 and many others. Because of the chaotic nature of so much of the Sawtooths, these won’t be very noticeable unless one was familiar with the boulder fields at the base of these slopes and a color difference on the faces because of the newly exposed granite.”

QUAKES ADD TO BACKLOG OF TRAIL MAINTENANCE

Sawtooth trails have also sustained some damage, mostly from falling rocks or avalanches shook loose by earthquakes.

According to Brian Anderson, deputy area ranger for the Sawtooth National Recreation Area, most of the infrastructure in his jurisdiction — trails, bridges, etc. — has remained intact through the shaking.

“We did have a number of places where we encountered large rockfalls that impacted trails,” Anderson said.

This summer, the Idaho Mountain Express reported Trail 101 was cut off by “a boulder the size of a two-story house.” That trail, which is near Redfish Lake, as well as one near Grandjean needed to be rerouted thanks to the debris. But that’s not the end of the work for the Forest Service.

“(The reroutes are) probably not long-term solutions, so we’ll have to see about getting the trails back in there,” Anderson said.

That’s easier said than done. Kelly Hughes, spokeswoman for the Idaho Trails Association, said she saw rockslides and other debris on the Alice-Toxaway Loop in the Sawtooths this summer. The incidents just add to an existing backlog of trail maintenance in the state.

“This kind of work is really hard,” Hughes said. “When part of the trail gets wiped out like that, it’s really not safe for people to go over.”

The Idaho Trails Association leads numerous volunteer maintenance trips each year on trails around Idaho. Hughes said clearing slide debris would be a challenge for their groups.

“You have to have people that are really up to that task,” she said. “Moving rocks is hard, hard work.”

Kathryn Grohusky, executive director of the Sawtooth Society, said she has also noticed avalanche fields across trails, though she’s not certain they were caused by earthquakes. Still, they contribute to the maintenance issues that the Sawtooth Society has also been working to address.

Despite the slides and the unpredictable rumbling, Anderson said there have been no reports of serious injuries as the result of quake activity. He reminded hikers and backpackers to be aware of the seismic activity if they’re recreating in the area.

“You might not think an earthquake is something you necessarily have to be concerned about,” Anderson said. “You’re smart to look for hazard trees over your campsite (that could fall) and make sure you’re mindful of steep slopes that could collapse under an aftershock.”

‘PROOF THAT THE EARTH IS ALIVE’

Cannady also emphasized the importance of safety in the Sawtooths, even when there’s not a threat of a temblor. He said he finds joy in the earthquakes — after all, they’re the same geological shifts that created the mountain range he loves so much.

“I’m damn sure not going to let the possibility of an earthquake keep me out of the Sawtooths,” he said. “I love the quakes because they are proof that the Earth is alive. When we feel a quake, it’s like we are feeling the Earth’s pulse. And the Earth’s heart beats on a very different time scale than we can even comprehend, so when we feel the shaking and see the changes, we are just witnessing a process that created the mountains we love so much.

“It can definitely be unnerving to have the ground move under you, when terra firma becomes unfirm,” he added. “But it is very natural, and we will likely recall the experience the rest of our lives.”