24-25

<p><span><span><span><strong><span><span>Wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> are the primary problem mostly from strong winds on Tuesday and late last week that blew generally from the W and some NW. On Tuesday, ski guides near Cooke City spotted a </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33805"><span><span><span><span><span><… ft wide wind slab</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> that released naturally.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Larger persistent slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> that could break on old faceted layers 1-2 feet above the ground have become much less frequent. The peak instability was almost two weeks ago after a long period of sustained snowfall following Christmas. With only light snowfall trickling in since then, the likelihood of triggering one of these has dropped significantly but the possibility remains.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Faceted layers of snow that cause persistent slab avalanches are like relationships - they can break in an instant, but take time to repair and build trust. With several large avalanches last week near Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33528"><span><span><span><span><span><…; and </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33544"><span><span><span><span><span><…;), one in the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33584"><span><span><span><span><span><… Madison Range</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, and one </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33790"><span><span><span><span><span><… sign of instability last Sunday near Cabin Creek</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, I need a little more time to build the trust to enter big terrain.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>For these reasons today the avalanche danger is MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Wind slab avalanches </span></span></strong></span></span></span><span><span><span><span><span><span>are the main problem in the mountains near Bozeman, Big Sky, and Island Park. To be honest, they are always a concern to varying degrees, and I’ve been fooled many times thinking wind slabs had stabilized only to find one that hadn’t. Increased winds today may form new, shallow wind slabs and keep older wind slabs unstable.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Today seek out slopes sheltered from the wind</span></span></strong></span></span></span><span><span><span><span><span><span>. Dave and his partner </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33816"><span><span><span><span><span><… this exact strategy yesterday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> in the northern Bridgers even though it was not easy to find a wind sheltered slope. Persistent slab avalanches are unlikely, and old weak layers have gained strength on most slopes where the snowpack is over about 5 feet deep.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is MODERATE on wind loaded slopes and LOW on non wind loaded slopes.</span></span></span></span></span></span></p>

<p>Wind slab avalanches will be the most likely problem today after yesterday's strong winds as well as strong winds from late last week. You'll surely find them under upper elevation ridgelines and cornices, but look for them at lower elevations where winds cross load gullies, subridges, and other terrain features. Yesterday in Sheep Creek near Cooke City, guides spotted a 200 ft wide wind slab that had released naturally. It may be harder to identify these areas with a few inches of new snow camouflaging the fresh wind slabs.</p>

<p>This wind loading will bump up the possibility of triggering a much larger persistent slab avalanche breaking on old weak layers of facets about 1-2 feet above the ground. These larger avalanches have become much less frequent with three spotted just over a week ago, and snowmobiler triggering deep shooting cracks on Sunday in the southern Madison Range.</p>

<p>Today in the southern Madison and Gallatin Ranges, in the Lionhead area near West Yellowstone, and in the mountains near Cooke City; the avalanche danger is MODERATE.</p>

<p>Wind slab avalanches are the main problem as well in the mountains near Bozeman, Big Sky and Island Park. Dave describes this problem well in his video from yesterday in Hyalite Canyon posted to YouTube. Fresh snow today will make it harder to identify these fresh wind slabs, but use your best judgement to estimate where winds deposited snow yesterday and avoid those slopes.</p>

<p>Persistent slab avalanches are unlikely, and old weak layers have gained strength on most slopes where the snowpack is over about 5 feet deep. Today in the Bridger Range, in the northern Gallatin and Madison Ranges, and the Island Park area, the avalanche danger is MODERATE on wind loaded slopes which are more widespread than not. Slopes sheltered from the wind without any recent wind loading have a LOW danger.</p>