Skier triggered avalanche on a sub-ridge of Wilson Peak that caught and injured a skier on 4/3/22.
Photo: GNFAC
We were skiing in the northern absarokas yesterday, and triggered a number of slow moving sluffs in the new snow that slid easily on the thick crust formed from the warmup last weekend. The sluffs were triggered in isolated steeper terrain (>38deg) but were able to pick up enough momentum to travel a ways downslope. We figured that a few more inches of load in the form of the new snow last night or windslabs forming on the ridgelines would make them more difficult to manage. We saw some shooting cracks at ridgelines due to wind slab development, but the attached image shows sluffs that traveled a fair bit down the slope, but didn’t propagate wider than the area affected by our skis.
We were skiing in the northern absarokas yesterday, and triggered a number of slow moving sluffs in the new snow that slid easily on the thick crust formed from the warmup last weekend. Photo: C. Avis
<p>In the Bridger Range, 4” of new snow will easily slide with above freezing temperatures and clear skies this afternoon. On steep slopes that have a firm crust under the new snow and receive direct sunshine later today, avalanches of the new snow could run far and become large enough to bury or injure a person. Monitor how wet or moist the snow surface is as temperatures warm, and get off steep slopes before the new snow becomes wet. Additionally, watch for signs of unstable fresh drifts, such as cracking across the snow around your feet or skis, rounded pillow-like snow features, or wind blowing snow off ridgelines. Fresh drifts will also be more reactive if they sit on a firm crust.</p>
<p>This morning large avalanches are unlikely and danger is LOW. Later today large wet loose avalanches will become possible and danger will rise to MODERATE.</p>
<p>Through the rest of the forecast area a person can trigger a small slab of recently wind-drifted snow or a small loose snow avalanche. Similar avalanches were triggered by skiers in Beehive Basin yesterday (<a href="https://www.mtavalanche.com/node/26412"><strong><u>details</u></strong>…;), and on Black Mtn. on Friday (<a href="https://www.mtavalanche.com/node/26409"><strong><u>details</u></strong>…;). Avalanches will involve 1-3” of new snow and probably be too small to bury a person, but even the smallest avalanche can knock you off your feet. Be cautious of steep slopes that have high consequences of being caught in a small slide, like above cliffs, rocks or trees.</p>
<p>It is unlikely to trigger a larger avalanche on deeper weak layers, but not impossible. Dave found buried weak snow in Hyalite a couple days ago (<a href="https://www.youtube.com/watch?v=0w18Fxp-dmI"><strong><u>Flanders video</u></strong></a>), and yesterday skiers north of Bridger Bowl found similar unstable snowpack test scores (<a href="https://www.mtavalanche.com/images/22/unstable-snowpack-test-north-brid…;). Before riding steep slopes, dig to double check that a poor or unstable snowpack structure does not exist. Stack the odds in your favor by only exposing one person at a time to avalanche terrain and always carrying proper rescue gear. Today, large avalanches are unlikely and the avalanche danger is LOW.</p>
<p>If you get out, please send us your observations no matter how brief. You can submit them via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</p>
From obs 4/2/22: "With the MSU Avy 2 class today. We dug 3 separate pits on the NE aspect off the top of Texas Meadows. Two pits had ECTX and one in between had an ECTP23 @ 55cm down failing on a persistent facet layer. Bottom half of the entire snowpack was still facets to the ground. Boot sunk to the ground once we reached that layer in the pit." Photo: C. Ellingson
Skier for scale next to the debris pile for a wet slide observed on 4/2/22. The slide appeared to be a few days old. Photo: H. Darby
From obs: "Saw a big natural wet slide on the way to bell lake today, right before the trail and the road split. Went to the ground and looked like it took out some mature timber in the debris pile." Photo: H. Darby
Observed on 4/2/22. Observers noted the slide appeared to be a few days old and took out mature timber.
From obs: "Today my partner and I skied the Peruvian Face on the N side of 10,602 in Beehive Basin. We originally were going to ski Bolivia. I went out into the start zone on belay and decided to turn around due to an 8” hard slaslab what appeared to be a decomposing, unsupportable sunsun cruste then scrambled the ridge to the top of Peru. After the good ol throw a rock and see what happens test, the start zone appeared to be soft and slightly loaded. I made a skiski cutross the top of the path and pulled out a 6-8” wind wind slabwide and ran 3/4 of the path. We then skied variable snow/debris to the bottom. There was evidence of wet loose activity from the previous warming on many aspects in the south fork of Spanish creek"
