22-23

<p>Dangerous avalanche conditions exist in the mountains across the advisory area. Eleven inches of fresh snow in the Bridger Range and 2-5” elsewhere adds to six straight days of cumulative loading. West Yellowstone and Cooke City have received near constant snowfall for more than two weeks. Consider two problems today. The first, is deep slab avalanches that could fail multiple feet deep. The second, is slides within the new and wind-drifted snow. The latter is slightly less dangerous but more likely. The former is less likely but potentially unsurvivable.</p>

<p>Deep slab avalanches keep us on edge and should keep you on edge too because signs of instability before triggering an avalanche are less likely, snowpack tests are often unreliable and multiple people may ski or ride a slope before it releases. Manage deep slab avalanche by avoiding slopes over 30 degrees and minimizing time below them. Staying in lower elevation or non-wind-loaded terrain reduces but does not eliminate your chances of triggering a deep slab avalanche.</p>

<p>In Cooke City, five human-triggered avalanches have failed in the last week, with four partial burials (<strong><a href="https://www.mtavalanche.com/node/28478">Miller Mountain</a></strong>, <a href="https://www.mtavalanche.com/node/28338"><strong><span>Town Hill</span></strong></a>, <a href="https://www.mtavalanche.com/node/28322"><strong><span>Round Lake</span></strong></a>, <a href="https://www.mtavalanche.com/node/28331"><strong><span>Mt. Abundance</span></strong></a>). Doug investigated the most recent skier-triggered avalanche that failed 4 feet deep on Thursday and found that it broke on a layer of buried surface hoar on a slope barely over 30 degrees steepness (<a href="https://www.youtube.com/watch?v=nZFM_QZxG3Q&amp;list=PLXu5151nmAvTi1DBS…;). This weekend, skiers triggered a four-and-a-half-foot deep avalanche on Hyalite Peak that caught and partially buried one of them (<a href="https://www.mtavalanche.com/node/28455"><strong><span>details and photos</span></strong></a>). Outside our advisory area in the Absaroka Range, a number of people skied and boarded a slope before one triggered a large slide and was injured, requiring helicopter evacuation (<a href="https://www.mtavalanche.com/node/28462"><strong><span>details and photos</span></strong></a>). Other recent avalanches across the advisory area are a clear sign that buried weak layers are a real concern (<a href="https://www.mtavalanche.com/images/23/snowmobiler-triggered-slide-buck-… Ridge Rider triggered</span></strong></a>, <a href="https://www.mtavalanche.com/images/23/sled-triggered-avalanche-cabin-cr… Creek rider triggered</span></strong></a>, <a href="https://www.mtavalanche.com/images/23/natural-avalanche-sage-basin-3"><… in Sage Basin</span></strong></a>).</p>

<p>Remember also the threat posed by smaller avalanches in the new and wind-drifted snow. Yesterday, Alex saw cracks shooting from the skis of his sled at Buck Ridge (<strong><a href="https://www.youtube.com/watch?v=-SJTky6-3wg">video</a></strong&gt;), and a group in the Northern Bridger Range found sensitive slabs breaking 5-10” deep (<strong><a href="https://www.mtavalanche.com/node/28482">details and photos</a></strong>). On Saturday, a pair of skiers triggered a wind slab on Elephant Mountain in Hyalite Canyon in high-consequence terrain (<a href="https://www.mtavalanche.com/node/28451"><strong><span>photos and details</span></strong></a>). Move on if you observe signs of instability and consider terrain features like trees, cliffs or gullies that increase the consequences of getting caught in a small slide.</p>

<p>The danger is CONSIDERABLE.</p>

<p><span>Please share avalanche, snowpack or weather observations via our<a href="https://www.mtavalanche.com/node/add/snow_obs"><span&gt; </span></a><a href="https://www.mtavalanche.com/node/add/snow_obs"><strong><span>website</s…;, email (<strong>mtavalanche@gmail.com</strong>), phone (406-587-6984), or Instagram (#gnfacobs). </span></p>

<p><span>Dangerous avalanche conditions exist in Island Park. Six inches of snow fell yesterday, adding to over two weeks of nearly constant loading </span><span>(<a href="https://www.mtavalanche.com/node/28422"><strong><span>recent observation</span></strong></a>)<span>. Slab avalanches failing multiple feet deep are possible. </span>The most reliable management strategy relative to deep slab avalanches is avoiding slopes over 30 degrees. Staying in lower elevation or non-wind-loaded terrain reduces but does not eliminate your chances of triggering a deep slab avalanche. </span></p>

<p><span>Slides within the new and wind-drifted snow are likely. </span>Move to different terrain if you observe signs of instability and consider terrain features like trees, cliffs or gullies that increase the consequences of getting caught in a small slide.</p>