17-18

<p>A snowmobiler from Idaho Falls is missing and presumed dead near Reas Peak on the Caribou-Targhee National Forest in the Centennial Range. His snowmobile was found partially buried in avalanche debris but he is unaccounted for. The rescue will continue today. Read a short clip from the East Idaho News <a href="https://www.eastidahonews.com/2018/01/update-search-for-i-f-man-killed-…;. We will update this post as more information becomes available.</p>

<p>Although the Centennial Range is out of our forecast area, it has a similar snowpack structure to the Lionhead area and mountains around West Yellowstone. The southern mountains have received a heavy amount of snow over the past 36 hours and the snowpack remains under a tremendous amount of stress. Facets buried 2-4’ deep are the primary concern and slides failing on this layer will be large and dangerous (<a href="https://youtu.be/e9OACzfb7pQ"><strong>video</strong></a&gt;, <a href="https://www.mtavalanche.com/images/18/poor-snowpack-structure-lionhead"…;, <a href="https://www.mtavalanche.com/images/18/instability-teepee-basin">photo</…;). It will be possible to trigger entire slopes from the bottom or from a distance and travel in avalanche terrain is not recommend.</p>

<p>As more snow and wind impact the area today, very dangerous avalanched conditions exist. Natural and human triggered avalanches will be likely on wind loaded slopes which have a <strong>HIGH</strong> avalanche danger. Human triggered avalanches are likely on non-wind loaded slopes which have a <strong>CONSIDERABLE </strong>avalanche danger.</p>

<p>Over the past day and a half, the mountains around Bozeman, Big Sky and Cooke City picked up 12 to 16” of snow totaling 1 to 1.5” of SWE. The snowpack in these areas is stronger than the mountains around West Yellowstone and was able to handle the recent load better. Yesterday, I skied in Beehive Basin near Big Sky and did not observe any signs of instability or recent avalanche activity. We found the new snow well bonded to the old surface and reluctant to move.</p>

<p>However, the Big Sky Ski Patrol actively triggered fresh winds slabs during control work yesterday morning. This problem seemed to be confined to terrain at or above treeline. Today, wind loaded slopes will be the primary avalanche concern. With more snow and wind in the forecast, wind slabs will grow in size and distribution as the day progresses. Watch for signs of instability such as cracking and collapsing and avoid steep slopes with wind drifted snow.</p>

<p>While most avalanches will stay confined within the storm snow, there is the possibility for slides to fail on facets buried 2-4’ deep. This instability is not widespread, but should be looked for and assessed before skiing or riding steeper slopes.</p>

<p>Today, human triggered avalanches are likely on wind loaded slopes which have a <strong>CONSIDERABLE</strong> avalanche danger. Non-wind loaded slopes have a <strong>MODERATE</strong> avalanche danger.</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>