21-22

<p>In the mountains near Cooke City 2-3 feet of snow fell since Wednesday equal to 3” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314… water equivalent</a> (SWE). Avalanches breaking in the new snow are likely, especially where it has been drifted into stiffer slabs. For the last couple weeks these mountains received steady snowfall with minimal avalanche activity reported. But don’t let your guard down. A snowpack can’t be trusted until it has time to adjust and show how it holds up to each storm. Today, more snow and moderate southwest winds mean avalanche conditions remain dangerous. A person can trigger an avalanche breaking below recent new snow, and possibly deeper in the snowpack which would be large and potentially deadly. Stay off and out from underneath slopes steeper than 30 degrees. The avalanche danger is rated CONSIDERABLE.</p>

<p>Near West Yellowstone and in the southern Madison and southern Gallatin ranges dangerous avalanche conditions exist where moderate to strong southerly wind has drifted snow into fresh slabs. These wind slabs will be unstable today as they grow larger with additional snow and wind. Since Wednesday these mountains received 2 feet of snow (1.8-2.5” SWE). Avalanches can break multiple feet deep below the recent snow, or possibly break larger on deeper buried weak layers. We have seen signs that buried weak layers are potentially unstable (<a href="https://youtu.be/7EEn6f8-4fA"><strong>Lionhead snowpack video</strong></a>, <strong><a href="https://www.mtavalanche.com/node/25196">Lionhead avalanches</a></strong>, <strong><a href="https://www.mtavalanche.com/images/21/teepee-basin-avalanche-1-0">Tepee avalanches</a>,</strong> <a href="https://www.mtavalanche.com/node/25253"><strong>Bacon Rind collapses</strong></a>), but right now these instabilities do not appear widespread. This indicates some slopes are stable, but we must remain cautious. Today, as the snowpack receives additional weight of new snow and drifts, avoid wind-loaded slopes steeper than 30 degrees and allow time for the snowpack to be tested by this storm (<a href="https://youtu.be/rdVk9B7UbtQ"><strong>Taylor Fork video</strong></a>). Danger is CONSIDERABLE on wind-loaded slopes and MODERATE on all other slopes.</p>

<p>The Bridger Range, Hyalite and Big Sky received 3-10” of snow (0.3-0.7” SWE) on Friday and can expect a few inches today. Avalanches are possible to trigger where this snow is drifted into stiffer, thicker slabs. Yesterday a natural avalanche broke on a steep, wind-loaded slope on Saddle Peak (<strong><a href="https://www.mtavalanche.com/images/21/natural-avalanche-saddle-peak-1">…;), and skiers in Beehive saw a recent cornice fall (<strong><a href="https://www.mtavalanche.com/images/21/cornice-failure-9200-e-beehive">p…;). Watch for signs that drifts of new snow are unstable, such as fresh avalanches or cracks in the snow from your skis. If you see these signs&nbsp;stay off steep, freshly wind-loaded slopes. Right now avalanches breaking deeper in the snowpack are not likely (<a href="https://www.youtube.com/watch?v=_MhpDHnH8So"><strong>Saddle Peak video</strong></a>, <a href="https://youtu.be/cf-qqv2Ssjw"><strong>Buck Ridge video</strong></a>, <a href="https://youtu.be/ePMCJs3qAs0"><strong>Beehive video</strong></a>), but we are still keeping an eye out for unstable buried weak layers. Today, the avalanche danger is MODERATE on wind-loaded slopes and LOW on all others.</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>

<p>Since Wednesday the mountains near Cooke City got 2&nbsp;feet of snow equal to 2.4” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314… water equivalent</a> (SWE), and over the last week received at least 4 feet of snow equal to 3.8” SWE. While this new snow is&nbsp;welcome, it creates dangerous avalanches conditions today. Avalanches breaking in the new snow are likely, especially where snow is drifted into stiffer slabs. The snow that fell over the last week makes up 30% of the total snowpack (measured in SWE) near Cooke City. This is a relatively heavy weight for the snowpack and any weak layers need time to adjust. The additional weight of a person could&nbsp;tip the scales and trigger an avalanche deeper in the snowpack which would surely be large and potentially deadly. Today it is best to stay off and out from underneath slopes steeper than 30 degrees. Human triggered avalanches are likely and the avalanche danger is rated CONSIDERABLE.</p>

<p>Near West Yellowstone and in the Southern Madison and Gallatin ranges 14-20” (1.3 to 1.9” SWE) of snow fell since Wednesday. Today avalanches involving this new snow are possible to trigger. Increased wind speeds will form stiffer slabs of wind-drifted snow which a person could trigger. Ian and I rode in Taylor Fork yesterday and saw minimal signs of instability in the new snow (<strong><a href="https://youtu.be/rdVk9B7UbtQ">video</a></strong&gt;), but that could change with more wind today. Avalanches could also break on weak layers near the ground (<a href="https://youtu.be/7EEn6f8-4fA"><strong>video</strong></a&gt;). Yesterday skiers near Bacon Rind reported collapsing and “whumphing” of the snowpack and stability tests breaking on buried weak layers (<strong><a href="https://www.mtavalanche.com/node/25253">details</a></strong&gt;). Before riding steep slopes carefully assess the potential for unstable buried weak layers. If you suspect buried weak layers or see signs that new snow or fresh drifts are unstable, avoid steep slopes. Today avalanches are possible and the avalanche danger is MODERATE.</p>

<p>Yesterday morning the Bridger Range got 3-10” of snow (0.3-0.7” SWE) while Hyalite and Big Sky got 3-4” of snow (0.2-0.4” SWE). Today avalanches are possible to trigger where this new snow is drifted into stiffer, thicker slabs. Watch for signs that drifts of new snow are unstable, such as fresh avalanches or cracks in the snow from your skis. If you see these signs, stay off of steep freshly wind-loaded slopes. Right now avalanches breaking deeper in the snowpack are not likely (<a href="https://www.youtube.com/watch?v=_MhpDHnH8So"><strong>Saddle Peak video</strong></a>, <a href="https://youtu.be/cf-qqv2Ssjw"><strong>Buck Ridge video</strong></a>, <a href="https://youtu.be/ePMCJs3qAs0"><strong>Beehive video</strong></a>), but on Thursday Big Sky Ski Patrol used explosives to trigger a 5 ft deep avalanche that broke on weak snow near the ground. This is our reminder to not forget about the potential weak layers deeper in the snowpack. Today, the avalanche danger is rated MODERATE on wind-loaded slopes and LOW on all others.</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>