Snowpack and Avalanche Discussion
<p>Strong winds and new snow are increasing the likelihood of triggering an avalanche that breaks deeply on weak facets near the ground that exists from Lionhead through the Bridger Range. Stability decreased with 3-5” of new snow or 0.2-0.4” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE) from Lionhead through Big Sky. The Bridger and Northern Gallatin Range have only received 1” or 0.1” SWE, but 20-30 mph winds with 60 mph gust are creating unstable drifts. Strong winds and precipitation will continue to decrease stability throughout the day.</p>
<p>Yesterday, Doug rode at Lionhead and saw many avalanches associated with last week’s storm (<a href="https://www.youtube.com/watch?v=Feyz2_4aNmU"><strong>video</strong></a&…;) and I was at Bacon Rind observing a weak foundation that was still unstable four days after the last snowfall (<a href="https://youtu.be/XzPIY1Q1cKo"><strong>video</strong></a>).</p>
<p>We are reentering a period of increased instability. Careful snowpack assessment and cautious route selection are essential to travel on, underneath or adjacent to steep slopes. Avoid wind-drifted slopes likely to avalanche under the weight of a rider or skier. The avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on non-wind-loaded. As snowfall continues, the avalanche danger will increase.</p>
<p>The mountains around Cooke City received 3” (0.3” of SWE) in the last 24 hours with more forecasted throughout the day. Persistent weak layers exist on some slopes that have resulted in avalanches breaking 1.5-2’ deep, but they do not exist on all. Skiers and riders are identifying this layer of weak snow within the top 3’ of the snowpack. Human triggered avalanches will become more likely as snow builds up today. Read our <a href="https://www.mtavalanche.com/sites/default/files/accident-reports/2021-0… report</strong></a> from a nearly tragic avalanche on the Fin and look at photos on the website to get an idea of what these slides look like (<a href="https://www.youtube.com/watch?v=0x5E-7XHwG8&list=PLXu5151nmAvQDzKmH…; </strong><a href="https://mtavalanche.com/node/23690"><strong>details</strong></a><strong…; </strong><a href="https://mtavalanche.com/node/23690"><strong>1</strong></a><strong>, </strong><a href="https://mtavalanche.com/node/23710"><strong>2</strong></a><strong>, </strong><a href="https://mtavalanche.com/node/23732"><strong>3</strong></a>).</p>
<p>The avalanche danger is MODERATE and will increase as the storm adds weight and stress to the snowpack. Watch for signs of decreasing stability such as collapsing or “whumphing”, shooting cracks and new avalanches.</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>
Upcoming Avalanche Education and Events
See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming events and opportunities to check out:
