Windier then I expected today at me d elevations adjacent to Bridger while teaching Friends of GNFAC courses. Photos show lots of wind transport during the day.
Felt a few collapses while skinning.
From email: "LOTs of collapsing again today while breaking trail on low angled S, E and W aspects. Some collapses were quite large (100'+ diameter)."
From email "Observed a fresh slab avalanche on Mt. Henderson this morning. E, SE aspect, 9,900'. I skied up to investigate it and would estimate the size of the crown to be 2-4' deep and about 80' wide. Somewhat surprised by the size relative to the starting zone. Likely a natural avalanche (from about 36 hrs ago), but there were fresh sled tracks in the vicinity from yesterday, so possibly a remote trigger."
From email: "Observed a fresh slab avalanche on Mt. Henderson this morning. E, SE aspect, 9,900'... would estimate the size of the crown to be 2-4' deep and about 80' wide... Likely a natural avalanche (from about 36 hrs ago), but there were fresh sled tracks in the vicinity from yesterday, so possibly a remote trigger." Photo: B. Fredlund
Observed a fresh slab avalanche on Mt. Henderson this morning. E, SE aspect, 9,900'.
I skied up to investigate it and would estimate the size of the crown to be 2-4' deep and about 80' wide. Somewhat surprised by the size relative to the starting zone. Likely a natural avalanche (from about 36 hrs ago), but there were fresh sled tracks in the vicinity from yesterday, so possibly a remote trigger.
LOTs of collapsing again today while breaking trail on low angled S, E and W aspects. Some collapses were quite large (100'+ diameter).
Big Sky Ski Patrol intentionally ski cut an avalanche breaking on the weak snow near the ground during avalanche mitigation work on 12/8/23.
From email: "[An avalanche] released on a ski cut, breaking on facets above a basal crust, easterly aspect, just below tree line."
Photo: BSSP
Big Sky Ski Patrol intentionally ski cut an avalanche breaking on the weak snow near the ground during avalanche mitigation work on 12/8/23.
From email: "[An avalanche] released on a ski cut, breaking on facets above a basal crust, easterly aspect, just below tree line."
<p><span><span><span><span><span><span>Unstable snow is widespread at higher elevations across our advisory area. Yesterday, skiers and riders saw natural avalanches in Hyalite (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29403"><span><span><span><strong><span…;), got cracking and collapsing in Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29412"><span><span><span><strong><span…;), Island Park (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29417"><span><span><span><strong><span…;), Big Sky (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29419"><span><span><span><strong><span…;) and the Bridger Range (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29415"><span><span><span><strong><span…;) and Big Sky Ski Patrol intentionally ski cut an avalanche breaking on the weak snow near the ground during avalanche mitigation work (<strong><a href="https://www.mtavalanche.com/images/23/ski-cut-triggered-avalanche">phot…;). These are all signs the snowpack is unstable and ready to avalanche. Conditions remain primed for triggering avalanches today.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Weak snow at the ground that fell in October and early November has been overloaded by this week’s new snow. Any slope that held snow before last weekend is suspect. The thicker the slab of new snow, the more easily triggered and larger avalanches will be. As Alex and I found in the Bridger Range yesterday, even in parts of the advisory area that have less old snow as you gain elevation there is still plenty of weak snow at the ground to trigger slides (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=Mj__nOyNC0o"><span><span><span><strong>… Range video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). An observation of small natural slides in the Hyalite gullies yesterday is a good occasion for a reminder that even small slides need to be taken seriously in very steep terrain (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29411"><span><span><span><strong><span…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>If you ride on or beneath steep slopes today, expect to trigger avalanches. Avoid the hazard by sticking to lower angled slopes today and avoiding crossing runout zones beneath steeper slopes. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>From Bozeman to Island Park and in Cooke City, human triggered avalanches are likely and the avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>
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Cracking and collapsing reported across the advisory area in the Bridger Range, Big Sky area, near West Yellowstone and Island Park, and near Cooke City.
