West of Gilmore Summit in the Lemhi Range rises a 10,200′ twin-peaked unnamed summit. Our objective for Saturday was to ascend the east ridge then explore new terrain in Silver Moon Gulch. SMG offered south, east, and north facing terrain, so depending on snow conditions and/or avalanche concerns, the location provided several options. Our main objective was to explore this new (for us) peak, poke around a bit, and look at some possibilites for future exploration.
Tempratures were below freezing when we left the car and soft surface snow gave us hope that the Lemhis hadn’t experienced the forecasted radical warm temps. A cold breeze did not allow the sun to warm us too much as we skinned toward the peak. Once across the flats and climbing the ridge through the trees it was very apparent the snowpack was composed entirely of facets yet lacked any sort of noticeable cohesive slab.
After a few hours of hard uphill trenching we reached the summit around 2:30 in the afternoon. A strong breeze and cold temps kept us bundled up, and after a few summit shots, we hiked wind-blown bare ground and shallow snow patches toward the top of Silver Moon Gulch.
In route we talked about our descent plans:
- Big steep open slopes or couloirs were out of the question with the faceted snowpack
- Avoid south aspects that have been warmed by the sun
- Traverse south along the ridge to reach shaded, treed, more conservative terrain instead of the more open face/bowl directly below us into the Gulch
- Ski short pitches in the trees and stay in visual contact
Our traverse was easy and without incident or signs of slabs as we ski cut, poked at the snow, and dug quick hand pits; all of which still showed us “fist” soft facets. Once onto a shaded and treed east-northeast aspect we skied short pitches down the fall-line staying in visual contact… which proved to be very short pitches in the trees!
The slope angle was in the low 30’s and the faceted snow was enjoyable to ski. Around 9,500′ the slope angle increased at an obvious convexity. Turbo and I agreed we should move our group left onto lower angle terrain to avoid the steeper section below us and to the right. Heather and I waited in the trees above and right of Dave and Turbo while Turbo watched Dave traverse left (who was just below and slightly to his right). In the process of traversing left, Dave crossed the top end of a more open area between the trees and witnessed the slope buckle below him. He quickly continued left, stopping on the uphill side of a big tree.
SS-ARu-R2-D2.5-G ENE @9,500′; 250′(?) wide x 1,400′ fall
The slide started about 40′ wide on a 37* slope and as it ran down through the trees it widened out to approx 250′ in places. The crown was 40cm to 60cm and well-defined as the shallow snowpack released on a foundation of depth hoar at the ground. The weak interface was the difference in grain size between the fist hardness facets and the fist hardness depth hoar. Despite the often dense trees covering the slope, the soft, faceted snowpack ran silent and swift for several hundred vertical feet before spilling out of the trees and into the gulch below, cascading over a 20′ cliff, and finally coming to rest 1,400′ vertical feet below its point of origin.
This photo is looking up a portion of the slide path. It started several hundred feet further up into the trees. This photo easily shows the amount of anchoring vegetation which did not anchor the snow at all…
We regrouped and felt out safest option was to descend the avalanche path. This also allowed us to witness the size and destructive nature of the event first hand. Humbled, respectful and in awe as we followed the path through the trees and into the gulch below. It was obvious this event would have been fatal. We estimated the debris at the toe of the slide to be approx 20′ deep in places.
Youtube has a lot of rad videos of people escaping and/or surviving an avalanche or triggering an avalanche. Those involved seem elated about what they just did… as if to say… “F&$k yea… I’m so cool!!!”…
Our group did not do that. We reflected on the event. Felt scared. Felt humbled. Asked ourselves what we did wrong. Asked ourselves what we did right. Talked, listened, and reflected with each other all the way home only to part with hugs and an even greater appreciation for traveling in the backcountry with loved friends who respect the mountains and who share the same agenda of coming home at night after learning from and enjoying the mountains.
Nibbling on Lemhi terrain is a good idea for anyone wanting to sample the skiing it offers, but be aware even nibbling has its hazards. I’m glad we nibbled on Saturday and didn’t just jump into the biggest line on the peak. This event reinforced our efforts to use safe travel habits and confirmed our belief that micro-managing terrain top to bottom is imperative. We didn’t let our guard down with the untrustworthy snowpack and we were rewarded. We avoided “extreme” terrain and traveled with our caution radar on high and it paid off… but we still dodged a bullet. Backcountry skiing is hazardous and avalanches will occur. How people manage the hazard is the key to success.