Snowpack and Avalanche Discussion
<p>The mountain ranges near West Yellowstone and Cooke City received 12-14” of new snow equal to 1.2-1.6” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE) since Saturday. In Cooke City a snowmobiler triggered two slab avalanches on Sunday, the bigger of the two broke a foot deep and 100’ wide (<strong><a href="https://www.mtavalanche.com/node/22425">photos and details</a></strong>). Skiers saw many avalanches within the new snow (<a href="https://www.mtavalanche.com/node/22427"><strong>details</strong></a>, <a href="https://www.mtavalanche.com/images/20/natural-avalanche-upper-republic-…;). On Sunday, skiers near Hebgen Lake reported that the new snow avalanched in steep terrain with ski cuts (<strong><a href="https://www.mtavalanche.com/node/22443">details</a></strong>). The new snow is stabilizing but watch for and avoid areas where shooting cracks from your skis or sled indicate continued instability.</p>
<p>Increasing clouds should minimize the wet snow danger today. However, if the sun stays out as the day warms, the wet snow danger will rise and avalanches will be possible. If you observe natural activity or pinwheels on south-facing slopes, move to shadier north-facing aspects that hold dry snow.</p>
<p>The danger is rated MODERATE and human triggered avalanches are possible. Assess slopes for dry snow instability and watch for signs of snow surface warming if you are considering entering avalanche terrain today.</p>
<p>Saturday through Sunday night the mountains around Big Sky received 9” of new snow (0.9” SWE) with 4” (0.4” SWE) in the mountains around Bozeman. Yesterday in Frazier Basin, we observed six wet, loose avalanches and intentionally triggered a small cornice and wind slab before committing to our ski objective (<a href="https://www.youtube.com/watch?v=4RMSu675sjM&list=PLXu5151nmAvSbcbVf…;). On Sunday in Middle Basin, Doug tested the new snow and found it was bonding well at the interface (<a href="https://www.youtube.com/watch?v=FVd85tHEySQ&list=PLXu5151nmAvSbcbVf…;, <a href="https://www.mtavalanche.com/images/20/snowpit-beehive"><strong>photo</s…;). Nearby on the same day, the Big Sky Ski Patrol was dealing with fresh drifting and rapid cornice growth. Without new loading, the drifts that avalanched the last two days will stabilize, but I don’t trust them yet. Avoid or test fresh pillows of snow as human triggered avalanches are possible in these areas.</p>
<p>Increasing clouds should minimize the wet snow danger today. However, conditions change rapidly this time of year. If you observe natural activity or pinwheels on south-facing slopes, move to shadier north-facing aspects that hold dry snow.</p>
<p>The avalanche danger is MODERATE on wind loaded slopes and solar aspects <em>if</em> the sun stays out. The danger is LOW everywhere else. Avoid wind loaded starting zones and watch for signs of snow surface warming as signs of instability if you are considering entering avalanche terrain today.</p>
<p>If you get out, please send us your observations no matter how brief. You can fill out an <a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank">observation form</a>, email us (<a href="mailto:mtavalanche@gmail.com" target="_blank">mtavalanche@gmail.com</a>), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>
Upcoming Avalanche Education and Events
Upcoming avalanche education programs have been canceled due to the coronavirus. Thank you to all our amazing instructors for a great year of education. We appreciate you!
