18-19

<p>The mountains near West Yellowstone and the southern Madison and southern Gallatin ranges have an unstable snowpack with 1.5’ of weak, sugary facets on the ground. Snowfall and wind last week loaded this weak snowpack, and avalanches occurred naturally. Doug saw evidence of these avalanches last Tuesday on Lionhead Ridge near West Yellowstone (<u><strong><a href="https://www.youtube.com/watch?v=1Z5eDFItVF4&amp;t=0s&amp;index=2&amp;li…;, <u><strong><a href="https://www.mtavalanche.com/images/19/natural-avalanche-lionhead-ridge"…;). On Thursday, Eric experienced large collapses and unstable test results at Bacon Rind (<u><strong><a href="https://www.youtube.com/watch?v=zj26vpS2WE0">video</a></strong></u&gt;). Yesterday I rode into Cabin Creek from the Taylor Fork and found similar unstable conditions. Our sleds easily broke through 2.5’ of snow to the ground, a sign of poor snowpack structure (<strong><a href="https://www.youtube.com/watch?v=l0aklSLqYaM&amp;list=PLXu5151nmAvRNl9ku…;, <strong><a href="https://www.mtavalanche.com/images/19/poor-structure-s-madison-range">p…;).</p>

<p>No snow since Monday has allowed the snowpack to gain strength and avalanches are relatively harder to trigger than earlier in the week. However, recent collapsing and unstable test results, large avalanches last Monday, and an unsupportive snowpack are signs to avoid avalanche terrain. Large avalanches are possible to trigger today and avalanche danger is <strong>MODERATE</strong>.</p>

<p>In the mountains near Bozeman and Big Sky thick drifts of snow that formed from strong wind earlier in the week are possible to trigger. The last two days, skiers in Hyalite and the Bridgers observed crowns of natural avalanches that broke earlier this week on wind loaded slopes (<strong><a href="https://www.mtavalanche.com/images/19/old-crown-near-hyalite-peak">phot…;, <strong><a href="https://www.mtavalanche.com/images/19/slab-avalanche-bridger-peak">phot…;). An equally possible place to trigger an avalanche is on slopes with a relatively shallow snowpack where weak, sugary snow underlies a cohesive slab. Eric found this unstable snowpack structure on Mt. Ellis (<u><strong><a href="https://www.youtube.com/watch?v=jnXlxSi2MRE&amp;list=PLXu5151nmAvRNl9ku…;, <u><strong><a href="https://www.mtavalanche.com/images/19/buried-facets-wilson-peak">photo<…;), and the last two days skiers in Hyalite and Beehive reported collapsing (<strong><a href="https://www.mtavalanche.com/images/19/collapse-and-whumph-beehive">phot…;). Carefully assess for recent wind loading and a poor snowpack structure. If either exists, consider different or low angle terrain. Today, avalanches are possible to trigger and avalanche danger is <strong>MODERATE</strong>.</p>

<p>The mountains near Cooke City have had less recent snow and wind than the rest of the area, and have a relatively stronger snowpack. Doug was in Cooke City last week and found a couple weak layers of concern (<strong><a href="https://www.youtube.com/watch?v=W6iS9ManzPo&amp;t=0s&amp;list=PLXu5151n…;, <strong><a href="https://www.youtube.com/watch?v=4Vb2Y4UZJ1Q&amp;t=0s&amp;list=PLXu5151n…;), but minimal loading from snow and wind makes avalanches unlikely on these weak layers. Wind earlier this week formed drifts of snow that can be triggered near ridgelines, below rock outcroppings, and on cross loaded terrain features (<u><strong><a href="https://www.mtavalanche.com/images/19/crown-butte-avalanches-1">photo</…;). These wind slabs have gained strength and will be difficult to trigger today, but not impossible. Minimal recent loading and no widespread buried weak layers make avalanches unlikely today and avalanche danger is <strong>LOW</strong>.</p>

<p>If you get out and have any avalanche or snowpack observations to share, contact us via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u&gt;, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u&gt;), phone (406-587-6984), or Instagram (#gnfacobs).</p>