20-21

<p>The southern ranges received 4-6” of new snow equaling 0.2-0.4” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE) and strong winds are actively blowing and drifting the fresh snow onto a weak foundation of sugary facets as Doug observed at Lionhead yesterday (<a href="https://www.youtube.com/watch?v=N2PYLeN5iUc"><strong>video</strong></a&…;). Snowfall and wind drifting will continue today, heightening the avalanche conditions on all slopes and creating dangerous avalanche conditions on slopes with fresh drifts where human triggered avalanches will be likely. <a>Avoid steep wind-loaded slopes and look for obvious signs of instability such as recent avalanche activity, “whumphing,” and shooting cracks from your sled or skis </a>before entering any avalanche terrain.</p>

<p>The avalanche danger is rated CONSIDERABLE wind-loaded slopes and MODERATE on all other slopes.</p>

<p>The northern ranges received 1-3” of new snow (0.1-0.2” SWE) with strong west to southwest winds. The snowpack structure is weak and human triggered avalanches are possible on slopes where the wind deposited drifts are loading the shaky foundation. Yesterday, north of Bridger Bowl, Ian and I noted that a slab was the missing ingredient before we see avalanches, our current weather will complete the recipe (<strong><a href="https://www.youtube.com/watch?v=JrjrgTLRff0">Ramp</a&gt; </strong><a href="https://www.youtube.com/watch?v=JrjrgTLRff0"><strong>video</strong></a&…;). This same story applies to all the ranges around Bozeman and Big Sky (<a href="https://www.youtube.com/watch?v=cUnquoQ5kXU"><strong>Beehive video</strong></a>, <a href="https://youtu.be/aqBSydiYMYk"><strong>Hyalite video</strong></a>, <a href="https://www.youtube.com/watch?v=NDfD3-tTguk"><strong>Saddle Peak video</strong></a>, <a href="https://www.youtube.com/watch?v=4quJW8upKQg"><strong>Buck Ridge video</strong></a>). On non-wind-loaded slopes, the new snow’s weight is not enough to increase the avalanche danger and human triggered avalanches will be limited to isolated areas in steep, rocky terrain. Watch for signs of instability and dig a quick snowpit before entering any avalanche terrain (<a href="https://www.youtube.com/watch?v=Gk8W8nlUMpw&amp;list=PLXu5151nmAvQDzKmH…;

<p>Today the avalanche danger is rated MODERATE on wind-loaded slopes and LOW on all other slopes.</p>

<p>Lacking the widespread weak layers found in the rest of our advisory area, the snowpack in Cooke City will support yesterday’s 3” of new snow (0.2” SWE). Avalanches will be small and confined to the recent snow in steep and extreme terrain. These slides can have outsized consequences if they push a rider or skier into terrain traps such as rocks, trees, and cliffs. Assess the snowpack before entering avalanche terrain and use safe travel practices by only exposing one person at a time and carrying all avalanche rescue equipment.</p>

<p>Today the avalanche danger is LOW in the mountains around Cooke City.</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>

<p>Snow tapered off yesterday in the mountains around Bozeman, Big Sky, and West Yellowstone with snow totals ranging from 5 to 8” equal to 0.3-0.4” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a> (SWE) since Friday. Yesterday, moderate west winds in the Bridger Range created small drifts near ridgelines (<a href="https://www.mtavalanche.com/images/20/cracking-drifted-snow"><strong>ph…;). Light winds in the rest of our area did not move much snow. These ranges have a weak foundation that will avalanche when loaded with a slab of new or wind drifted snow, but we are not there yet (<a href="https://www.youtube.com/watch?v=cUnquoQ5kXU"><strong>Beehive video</strong></a>, <a href="https://youtu.be/aqBSydiYMYk"><strong>Hyalite video</strong></a>, <a href="https://www.youtube.com/watch?v=NDfD3-tTguk"><strong>Saddle Peak video</strong></a>, <a href="https://www.youtube.com/watch?v=4quJW8upKQg"><strong>Buck Ridge video</strong></a>, <a href="https://www.youtube.com/watch?v=pKWi6VcTnzI"><strong>Lionhead video</strong></a>).</p>

<p>Instabilities today will be limited to loose snow avalanches in steep, rocky terrain like those I observed in Hyalite (<a href="https://mtavalanche.com/images/20/loose-snow-avalanche-divide-cirque"><…;) and Beehive (<a href="https://mtavalanche.com/images/20/small-loose-snow-avalanches-beehive">…;) in the last two days and isolated drifts of snow. These small avalanches could have outsized consequences if they push a skier or rider into obstacles such as trees or off cliffs. They are occasionally entraining the weak, faceted snow near the ground and gaining volume (<a href="https://www.mtavalanche.com/images/20/full-depth-facet-sluff-s-madison"…;).</p>

<p>Be obsessed about the consequences of small avalanches and carefully assess the snowpack looking for isolated instabilities before entering avalanche terrain. Today, avalanches are unlikely and the danger is LOW.</p>

<p>The snowpack around Cooke City is stronger and deeper than the rest of our advisory area and it is supporting the 4” of new snow (0.3” SWE) from this weekend. While the snowpack is generally strong, skiers and riders have found slopes with weak layers of surface hoar and sugary facets (<a href="https://www.youtube.com/watch?v=Xj-qhUPJigw"><strong>video</strong></a&…;, <a href="https://www.mtavalanche.com/images/20/surface-hoar-near-goose-creek"><s…;). Dig down to assess the snowpack to look for these instabilities. Learn how and what to look for in Doug and Bruce Jamieson’s recent ECT <a href="https://www.youtube.com/watch?v=Gk8W8nlUMpw&amp;list=PLXu5151nmAvQDzKmH…;. Instability today is limited to isolated drifts of snow and small, loose snow avalanches in steep, technical terrain that can knock a rider or skier off their sled or feet.</p>

<p>Carefully assess the snowpack and consequences of a small slide before entering avalanche terrain. Today the avalanche danger is LOW.</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>