19-20

<p>The southern ranges near West Yellowstone have the weakest snowpack structure in our advisory area and, in the last two days, they received the most snow. With 10-16” equal to 1-1.4” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE) (<a href="https://www.youtube.com/watch?v=QoHpKz6J52s&amp;feature=youtu.be"><stro…;) and 4-8” forecast today, dangerous avalanche conditions persist. The most likely avalanches will occur within the new snow and in areas where the wind is depositing large drifts of snow, but large avalanches failing on weak layers near the ground are possible as new snow stresses the snowpack (<a href="https://www.mtavalanche.com/images/19/shallow-and-unstable-lionhead"><s…;, <a href="https://www.mtavalanche.com/sites/default/files/styles/very_large_1200w…;). Either of these avalanche concerns will be large enough to bury, injure, or kill a skier or rider. Today, careful route finding to avoid steep slopes and runout zones will keep you out of harm’s way. The avalanche danger is CONSIDERABLE on all slopes.</p>

<p>Yesterday in Cooke City, skiers approaching Meridian Peak remotely triggered an avalanche that broke 15” deep and 50’ wide (<strong><a href="https://www.mtavalanche.com/node/21575">avalanche activity</a></strong>). This avalanche was relatively large on the path in which it occurred and gives us a window into what could happen on a bigger slope. While I was pleasantly surprised by the stability I found in my snowpits there the last two days, the key information is that more than 50” of snow fell since New Year’s Day and we saw large plumes of snow create by the wind (<a href="https://youtu.be/Za-GgO09eEw"><strong>video</strong></a&gt;, <strong><a href="https://www.youtube.com/watch?v=_VHfcZztwYQ">video</a&gt;, <a href="https://www.mtavalanche.com/images/20/wind-loading-cooke-city">photo</a…;).</strong> Avalanches breaking within freshly deposited drifts of snow will be large and avalanches breaking on weak layers deep in the snowpack will be deadly and remain a consideration. Avoid steep wind loaded slopes and assess non-wind loaded terrain before entering avalanche terrain. The avalanche danger is CONSIDERABLE on wind loaded slopes and MODERATE on non-wind loaded slopes.</p>

<p>The weak snowpack structure near Big Sky is producing avalanches. On Sunday, Doug saw three natural avalanches that broke near the ground in the Buck Ridge area (<strong><a href="https://www.mtavalanche.com/node/21558">avalanche activity</a></strong>, <a href="https://youtu.be/hVWTWK_GaBs"><strong>video</strong></a&gt;). The Big Sky Ski Patrol continues to trigger meaty wind slabs and an occasional deep slab avalanche. In the Bridger Range, the wind picked up in the afternoon transporting new snow. Yesterday, skiers north of Bridger Bowl reported a human triggered soft slab avalanche breaking 18-24” deep (<a href="https://www.mtavalanche.com/node/21572"><strong>avalanche activity</strong></a>). Give special consideration to slopes with freshly drifted snow and assess all steep slopes to determine the risk of larger avalanches before entering avalanche terrain. Human triggered avalanches are possible and the avalanche danger is MODERATE.</p>

<p>The Northern Gallatin Range has received less snow than the rest of our advisory area and has a generally strong snowpack. With 13” of new snow and 1” of SWE in the last six days, the primary concern is snow drifted by winds gusting into the 40s mph. Alex explains these issues in his <a href="https://www.youtube.com/watch?v=Fdgt5Mp8E6s&amp;list=PLXu5151nmAvSbcbVf…; from Mount Blackmore on Saturday. With continued winds and light snowfall forecast for today, avoid areas with freshly drifted snow and watch for cracks shooting out from your feet as signs of instability. Assess slopes for the consequences of small avalanches before committing to steep terrain. &nbsp;Avalanche danger is MODERATE on wind loaded slopes and LOW on non-wind loaded slopes.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an&nbsp;<a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>observat… form</strong></a>, email us (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>