17-18

<p>The Lionhead area outside of West Yellowstone picked up 8-10” of heavy snow overnight totaling .9” of SWE. This puts the three day total at over two feet of snow totaling 2.3” of SWE. The snowpack structure in this area is very weak and will be unable to support this heavy load (<a href="https://youtu.be/e9OACzfb7pQ"><strong>video</strong></a&gt;, <a href="https://www.mtavalanche.com/images/18/poor-snowpack-structure-lionhead"…;). Yesterday, a snowmobiler reported widespread cracking and collapsing while riding in this area (<strong><a href="https://www.mtavalanche.com/photos">photo</a></strong&gt;). People will easily trigger avalanches from the <u>bottom</u> of slopes on <u>flat </u>terrain. Today, natural and human triggered avalanches are likely and the avalanche danger is rated <strong>HIGH</strong> on all slopes.</p>

<p>The southern Madison and Gallatin Ranges and mountains around Cooke City have picked up 1.5 to 2’ of snow over the past three days totaling 1.5 to 2” of SWE. Fortunately, the snowpack in these areas is a bit stronger than the Lionhead area. Yesterday, Doug skied at Bacon Rind in the southern Madison Range and was pleasantly surprised by the strength of the snowpack (<strong>photo</strong>, <strong><a href="https://www.youtube.com/watch?v=gK10ZVPy7Wk&amp;list=PLXu5151nmAvQSYtIf…;). Skiers outside of Cooke City also noted the snowpack is handling the recent load surprisingly well.</p>

<p>With that said, facets buried 2-4’ deep remain a concern. This layer is stronger than it was a few weeks ago, but could easily become more reactive with the additional weight of new and wind-blown snow. Since the loading event just ended a few hours ago, I would be extra cautious when traveling in avalanche terrain today. Wind loaded slope will be the most prone to producing avalanches, but non-wind loaded slopes also hold the potential to produce large slides.</p>

<p>For this reason, the avalanche danger is rated <strong>CONSIDERABLE</strong> on all slopes.</p>

<p>The mountains near Bozeman and Big Sky have a stronger snowpack than the southern ranges. These areas also picked up less snow over the past 24 hours. Today, the primary concern in the mountains around Bozeman and Big Sky will be wind slabs. The combination of 4-6” of new snow and strong westerly winds will form dense slabs below ridgelines and on the leeward side of crossloaded terrain features. Yesterday, natural avalanches were observed on Saddle Peak south of Bridger Bowl (<strong><a href="https://www.mtavalanche.com/images/18/saddle-peak-slides">photo</a></st…;). These slides were the direct result of heavy wind loading. Today, fresh wind slabs will be touchy to human triggers and pose the greatest threat in steeper high consequence terrain.</p>

<p>There’s still the possibility for slides to break on facets buried 2-4’ deep. It has been a while since slides have failed on this layer, but it can’t be entire ruled out. This problem seems to be more confined to areas with a shallow snowpack. Keep this in mind when traveling on mid to low elevations slopes or areas where the snowpack depth is highly variable.</p>

<p>Today, the avalanche danger is rated <strong>CONSIDERABLE</strong> on wind loaded slopes and <strong>MODERATE</strong> on non-wind loaded slopes.</p>

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