21-22

<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>

<p>A big dump of new snow with strong winds means that human triggered avalanches are likely today. The Fisher Creek SNOTEL site is showing 18” (1.8” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314… Water Equivalent</u></a>) of snow over the last 48 hours and we’ve received reports of substantially more snow at higher elevations. You could trigger an avalanche within the new snow (especially in wind drifts), on a layer of weak snow in the middle of the snowpack, or on weak snow at the ground. Don’t get caught up in the details - with so much new snow, wherever a slide breaks it will be large and dangerous. Keep it simple. Stay off of and out from under any slope steeper than 30 degrees. Human triggered avalanches are likely and the avalanche danger is rated CONSIDERABLE.&nbsp;</p>

<p>With a foot of fresh snow (1.1” SWE) and strong southwest winds avalanches will break easily today on wind loaded slopes. Expect to trigger avalanches within the new snow and they could also break on the weak layers near the ground (<a href="https://youtu.be/7EEn6f8-4fA"><strong><u>video</u></strong></a&gt;). Look out for and avoid steep wind-loaded slopes. If you aren’t confident in identifying wind-loaded slopes, just avoid all steep slopes. The avalanche danger is CONSIDERABLE on wind-loaded slopes. On slopes without wind-drifted snow avalanches are possible and the avalanche danger is MODERATE.</p>

<p>Seven inches of new snow (0.7” SWE) isn’t enough to spike the danger, but does mean it’s possible to trigger dangerous avalanches on steep slopes that are either wind drifted or have weak snow at the base of the snowpack (<a href="https://youtu.be/2rjpm0iLm_I"><strong><u>Tepee Basin video</u></strong></a>). Look out for particularly deep wind-drifts or slopes where a small slide could pile up deeper in a gully or push you into obstacles. Human triggered avalanches are possible and the avalanche danger is MODERATE.</p>

<p>Fresh wind drifts are the primary concern near Bozeman and Big Sky. Yesterday, Alex and Doug triggered a small wind slab while looking at the snowpack on Saddle Peak (<a href="https://www.youtube.com/watch?v=_MhpDHnH8So"><strong><u>video</u></stro…;). With new snow and strong to extreme winds overnight, expect to find fresh reactive wind drifts on many slopes. While the lower snowpack is generally stable (<a href="https://youtu.be/cf-qqv2Ssjw"><strong><u>Buck Ridge video</u></strong></a>, <a href="https://youtu.be/ePMCJs3qAs0"><strong><u>Beehive video</u></strong></a>), yesterday, Big Sky Ski Patrol used explosives to trigger a 5 ft deep avalanche that broke on weak snow near the ground. Let this be a wake up call and reminder to not discount the basal weak layers that exist across our advisory area. 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><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

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