17-18

<p>Snow that fell at the end of last week created unstable slabs that broke naturally and were easily triggered by skiers (<a href="https://www.mtavalanche.com/images/18/avalanche-north-bridger"><strong>…;, <a href="https://www.mtavalanche.com/images/18/avalanches-west-saddle-peak"><str…;, <a href="https://www.youtube.com/watch?v=6LziSi4Boak"><strong>video</strong></a&…;). Near Bozeman and Big Sky these avalanches broke on lower density snow below a thick slab, which made them sensitive to human triggers for a couple days. Yesterday I found avalanches were possible on wind loaded slopes in the northern Bridger Range (<strong><a href="https://youtu.be/OW_9UbmG6b8">video</a></strong&gt;). These instabilities generally stabilize quickly. With little new snow this weekend and a lack of wind loading over the last 24 hours, avalanches are not likely or very small today.</p>

<p>Isolated small wind slabs or loose snow avalanches can be triggered and are harmful in the wrong terrain (e.g., above cliffs, dense trees, etc.). Cornices along ridgelines are massive throughout the advisory area. They can break farther back than expected and trigger larger slides below (<a href="https://www.mtavalanche.com/images/18/cornice-drop-cooke-city"><strong>…;, <strong><a href="https://www.mtavalanche.com/images/18/cornice-triggered-avalanche-near-…;). Avoid slopes directly below cornices and travel far back from the edge along ridgelines. Otherwise, the snowpack is 6-12 feet deep and generally stable (<a href="https://www.youtube.com/watch?v=NWVH97qURgs&amp;list=PLXu5151nmAvQSYtIf…;, <a href="https://youtu.be/kiUzoTR50MM"><strong>video</strong></a&gt;).</p>

<p>Avalanche danger today is rated <strong>LOW</strong>. Small and isolated instabilities exist. Practice safe travel, and continue to attentively assess terrain and snowpack.</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>

<p>The new snow that fell Thursday created unstable slabs 8-12” thick that are possible to trigger today. On Friday, we observed natural and human triggered avalanches near Bridger (<a href="https://www.mtavalanche.com/images/18/avalanche-north-bridger"><strong>…;, <a href="https://www.mtavalanche.com/images/18/avalanches-west-saddle-peak"><str…;) and in Beehive Basin (<a href="https://www.youtube.com/watch?v=6LziSi4Boak"><strong>video</strong></a&…;). Yesterday, skiers near the Throne reported cracking 6-10” deep and saw recent natural avalanches, and skiers in Hyalite triggered an avalanche 8-10” deep and 200’ wide (<strong><a href="https://youtu.be/BQSXgi3_zcI">video</a></strong&gt;). The recent snow formed a thick slab on top of lower density snow above an ice crust, which is stabilizing slowly (<strong><a href="https://www.mtavalanche.com/images/18/ramp-profile-16-mar">snowpit</a><…;).</p>

<p>Moderate wind over the last 24 hours drifted snow into thicker slabs. These fresh wind slabs are possible near ridgelines and along the base of cliffs, and found on a variety of aspects due to east to southwest wind directions. Be cautious of wind loaded slopes and slopes steeper than 35 degrees. Cracking of the snow surface on small rolls and test slopes is a clear sign to avoid steep terrain. Today, avalanches are possible to trigger and avalanche danger is <strong>MODERATE.</strong></p>

<p>The mountains near Cooke City and West Yellowstone got less snow (4-6” since Thursday) and don’t have signs of instability&nbsp;like the northern part of the advisory area. The primary concern today is fresh drifts of snow formed by moderate to strong east and southerly&nbsp;wind. These wind slabs are possible to trigger near ridgelines, and located on many aspects or unusual locations due to the wide range of wind direction.</p>

<p>Cornices along ridgelines are massive throughout the advisory area. Keep a far distance from the edge along ridgelines and avoid slopes below. Cornices can break farther back than expected and can trigger larger slides (<strong><a href="https://www.mtavalanche.com/images/18/cornice-drop-cooke-city">photo</a…;). Besides new snow instabilities and cornices, the snowpack is mostly stable and triggering a deeper avalanche is not likely (<a href="https://www.youtube.com/watch?v=NWVH97qURgs&amp;list=PLXu5151nmAvQSYtIf…;, <a href="https://youtu.be/kiUzoTR50MM"><strong>video</strong></a&gt;).</p>

<p>Moderate to strong wind over the last 24 hours formed wind slabs that are possible to trigger today, and avalanche danger is <strong>MODERATE</strong> on wind loaded slopes and <strong>LOW</strong> otherwise.</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>

<p>The snow that fell earlier this week was still sensitive yesterday, mainly in the Bridger Range. Alex skied north of Bridger Bowl and described conditions as “very reactive”. Storm slabs were breaking 10-12” deep, failing on a lower density layer of dendrites sitting over an ice crust (<strong><a href="https://www.mtavalanche.com/images/18/avalanche-north-bridger">photo</a…;, <strong><a href="https://www.mtavalanche.com/images/18/avalanches-west-saddle-peak">phot…;). I don’t expect conditions to be quite as touchy today, but I would still approach all avalanche terrain with caution.</p>

<p>The new snow wasn’t as reactive in Beehive Basin yesterday, but my partner and I observed a few natural avalanches in wind loaded terrain (<strong><a href="https://www.youtube.com/watch?v=6LziSi4Boak">video</a></strong&gt;). Today, all wind loaded slopes will remain suspect. Keep an eye out for recent wind loading near upper elevation ridgelines and watch for signs of instability such as cracking and collapsing. Avoiding wind loaded terrain and keeping slope angles less than 35 degrees will be a sure fire way to stay out of trouble.</p>

<p>Today, human triggered avalanches are possible and the avalanche danger is rated <strong>MODERATE</strong>.</p>

<p>The mountains around Cooke City and West Yellowstone don’t have the new snow instabilities that the northern ranges have. In general, the snowpack is mostly stable and the likelihood of triggering a slide is low (<a href="https://www.youtube.com/watch?v=NWVH97qURgs&amp;list=PLXu5151nmAvQSYtIf…;, <a href="https://youtu.be/kiUzoTR50MM"><strong>video</strong></a&gt;). With that said, human triggered avalanches can’t be entirely ruled out. This means standard backcountry protocol applies, which entails: everyone carries proper rescue gear and knows how to us it, only one person at a time is exposed to avalanche terrain and always watch your partner from a safe location.</p>

<p>Although generally safe avalanche conditions exist this morning, the avalanche danger could increase by this afternoon if the next storm hits earlier and harder than expected. Keep an eye out for blowing and drifting snow and avoid steep terrain if instability is on the rise.</p>

<p>Today, human triggered avalanches are unlikely and the avalanche danger is rated <strong>LOW</strong>. The avalanche danger could rise to <strong>MODERATE</strong> by this afternoon with the addition of new and wind-blown snow.</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>