20-21

<p>There are three distinct avalanche concerns across the advisory area today.</p>

<ol start="1" type="1">
<li><strong>Fresh Drifts of snow and wind-loaded slopes:</strong> For the last two days southwest to northwest winds blasted the mountains with gusts regularly reaching 70-85 mph with a peak of 104 mph at the summit of Big Sky two nights ago (<strong><a href="https://www.mtavalanche.com/images/21/wind-transport-wolverine-peak">Wo… Peak wind-loading</a>,</strong> <a href="https://www.mtavalanche.com/images/21/snow-transport-lone-mountain"><st… Sky wind transport photo</strong></a>). Winds stripped some slopes of all available soft snow and deposited drifts 1-3’ deep on others. Drifted slopes avalanched naturally on <a href="https://mtavalanche.com/node/24768"><strong>Saddle Peak</strong></a> in the Bridger Range, near <a href="https://mtavalanche.com/node/24755"><strong>Maid of the Mist</strong></a> (<a href="https://www.youtube.com/watch?v=IWqFF8GE__g&amp;list=PLXu5151nmAvQDzKmH…;) in Hyalite Canyon, and on <a href="https://mtavalanche.com/node/24752"><strong>Iceberg Peak</strong></a> near Cooke City and under the weight of skiers on <a href="https://mtavalanche.com/node/24766"><strong>Miller Mountain</strong></a>. Avoid steep slopes with on-going wind-loading or large pillows of recently drifted snow where small to large avalanches are possible.</li>
<li><strong>Persistent weak layers near the ground:</strong> This weekend skiers triggered an 8-10’ deep avalanche near Mount Blackmore (<a href="https://www.mtavalanche.com/node/24732"><strong>photos and details</strong></a>), others observed a natural deep-slab avalanche near Flanders Creek (<a href="https://www.mtavalanche.com/images/21/natural-deep-slab-near-flanders">…;), and snowmobilers triggered an avalanche that broke near the ground in McAtee Basin (<a href="https://www.mtavalanche.com/node/24748"><strong>photo and details</strong></a>). These are the first three slides to break on sugary snow at the base of the snowpack since February. Slides like this are a low probability, high consequence event and avoiding steep, complex slopes is the safest management strategy until this layer has fully adjusted to recent loading.</li>
<li><strong>Weak interface under recent snow:</strong> A weak layer of near-surface facets formed on some slopes, but not all, and was buried under 2-4’ of snow during the last 10 days. Skiers triggered avalanches at the interface between the old and new snow 7-10 days ago on Mount Blackmore (<a href="https://mtavalanche.com/node/24676"><strong>photo and details</strong></a>), Alex Lowe Peak (<a href="https://mtavalanche.com/node/24673"><strong>photos and details</strong></a>), and Hyalite Peak (<a href="https://mtavalanche.com/node/24668"><strong>photos and details</strong></a>) and we found it on some slopes around Buck Ridge (<a href="https://www.youtube.com/watch?v=JZ1rnPsoIIg&amp;list=PLXu5151nmAvQDzKmH…;) and Cooke City (<a href="https://www.youtube.com/watch?v=CZ27CVuKWuA&amp;list=PLXu5151nmAvQDzKmH…;). It hasn’t been reacting recently, but it is worth digging down and performing a quick stability test at this interface before committing to any steeper terrain (<a href="https://www.youtube.com/watch?v=sqn0KFZqXYs&amp;list=PLXu5151nmAvQDzKmH… V</strong></a><a href="https://www.youtube.com/watch?v=sqn0KFZqXYs&amp;list=PLXu5151nmAvQDzKmH…;
</ol>

<p>Human-triggered avalanches are possible today and the avalanche danger is rated MODERATE.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>