On our drive home we saw, what I assume were, natural wind-slab avalanches on Quarter Saddle (looked like a cornice collapse) and in Argentina Bowl. Bridger Peak was obscured by heavy wind-loading. Photo: GNFAC
On our drive home we saw, what I assume were, natural wind-slab avalanches on Quarter Saddle (looked like a cornice collapse) and in Argentina Bowl. Bridger Peak was obscured by heavy wind-loading. Photo: GNFAC
The wind was transporting significant amounts of the recent snow at high elevations. This is Naya Nuki loading as seen from the Ramp. Photo: GNFAC
The wind was transporting significant amounts of the recent snow at high elevations. This is Saddle Peak loading as seen from the Ramp. Photo: GNFAC
We toured up the Ramp. There was 6" of heavy new snow. The wind was transporting significant amounts of the recent snow at high elevations. The wind-loads weren't occurring on the ramp and lower elevation ridge terrain in a significant way. On our drive home we saw, what I assume were, natural wind-slab avalanches on Quarter Saddle (looked like a cornice collapse) and in Argentina Bowl. Bridger Peak was obscured by heavy wind-loading. There was a small wind-slab release out of Gibbs (I think), I suspect skier triggered, but I could make out a track.
On the Ramp, we observed several isolated drifts that would crack under the weight of skis. The snow was staying fairly cool and dry, but on a rollover, I pushed a small wet loose pocket downhill. Watch out when the sun and temps blast the recent snow! It is sitting on a firm crust and I expect things to get active.
We dug a pit to the south of the Ramp proper. The basal weak layers were the least weak I have seen all year. The snowpack was most from 80 cm to the ground and the facets and depth hoar are rounding. We are not out the woods, but things are improving. ECTN 20 on near-surface facets 30 cm from the top.
<p><span><span><span><span><span><span>In the mountains around Bozeman and Big Sky, 3-4” fell yesterday with another 2-3” last night. Even 15 mph wind was strong enough to create 6-8” wind slabs that avalanched naturally in the backcountry (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31616"><span><span><span><strong><span… Basin observation</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Last night’s snow and similar wind will create a few natural slides and conditions for people to easily trigger wind drifts, much like Alex found on Sunday on Buck Ridge (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=LlLu6b2UzU8"><span><span><span><strong>…;
<p><span><span><span><span><span><span>A secondary, but more consequential concern, are avalanches that break on weak snow found in the bottom third of the snowpack. These avalanches are deep and can propagate wide, but they are not easy to trigger. Possible ways are a cornice breaking or avalanche tumbling down the hill, or a person collapsing the weak layer from a thin area of the slope. Snowfall since Saturday, wind-loading in starting zones, and underlying weak snow near the ground leads me to give conservative travel advice. If you get into avalanche terrain do so incrementally, and find slopes that were not affected by the wind. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is CONSIDERABLE on all wind-loaded terrain and MODERATE on all others.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche potential in the southern mountains is two fold: shallow wind slabs which are easy to see, feel and mitigate, and a deeply buried weak layer which is difficult to trigger. Around Cooke City skiers saw and triggered a few wind slab avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31623"><span><span><span><strong><span… 1</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31615"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31598"><span><span><span><strong><span… 3</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Without fresh snow these will be more difficult to trigger today. Near the ground is weak snow that has been avalanching all winter, sometimes with just a few inches of snow or days after a storm. It’s been over a week since we had one reported. A trigger like a cornice breaking, or a person hitting a shallow part of a slope, could trigger a large avalanche. Even though the odds are going down it is not out of the question. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Dave and Ian were in Taylor Fork yesterday and found a thin layer of facets under the new snow and/or melt-freeze crust from last week. This layer easily broke in their stability test. Ian pointed out in his </span></span></span></span></span></span><a href="https://youtube.com/shorts/7JwEqf6PPj8"><span><span><span><strong><span…;, “Snowpits can shine to give us feedback” on the upper layers. As we travel into avalanche terrain, it’s not just the layers near the ground we are concerned with. Stability tests are pointing out weakness near the surface, a potential problem with more snowfall. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is rated MODERATE on all slopes.</span></span></span></span></span></span></p>
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Spent the last few days traveling around the Cooke City Area. New to the area so this is just some general notes/obs of things we saw that seemed interesting:
