17-18

<p>The snowpack is generally stable and the last reported avalanches were on Friday when ski patrols triggered small wind slabs. The backcountry only had a few wet sluffs on south-facing slopes. The snow depth varies from 5-6’ around Cooke City to 2.5’ in the northern mountains with all ranges harboring an ice crust that formed during Thanksgiving. In the absence of obvious signs of instability (cracking, collapsing or avalanches) we recommend digging and testing to this ice layer as a final step before dropping into avalanche terrain (<a href="https://www.mtavalanche.com/images/17/dig-thanksgiving-crust"><strong>p…;, <a href="https://youtu.be/io32nxnei0c"><strong>video</strong></a&gt;). On Monday in Hyalite my partner and I found stable conditions on the approach to Divide Peak and also in our snowpit (<strong><a href="https://www.mtavalanche.com/images/17/divide-peak-pit-profile">profile<…;).</p>

<p>If today’s storm arrives as expected, backcountry skiing and riding will improve but there will be a price to pay in the form of wind-loading and burying a new weak layer. A few inches of snow and wind may create 6-12” wind slabs at the ridgelines that could be triggered during and immediately after the storm. Additionally, the last 8 days of high pressure created a layer of small-grained facets (weak snow) at the surface which will get buried and cause avalanches in the future (<strong><a href="https://www.mtavalanche.com/images/17/small-faceted-grains">photo</a></…;). This layer is not widespread, but once buried it will require a bit of hunting to find. Stay tuned.</p>

<p>For today, the avalanche danger is starting out as <strong>LOW, </strong>but could rise with today’s snowfall.<strong> </strong></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>There’s been no new snow, no wind-loading and no recent avalanches. We have no reports of cracking or collapsing and stability tests are benign. The snowpack is generally stable. Buried 1-2’ deep is an ice crust that formed during Thanksgiving that we are using as a visual marker in the snow (<a href="https://www.mtavalanche.com/images/17/dig-thanksgiving-crust"><strong>p…;). Isolated instabilities (i.e. wind slab) would be found above this layer so we recommend digging to the crust and testing the snow, even during a low danger. Yesterday my partner and I skied Divide Peak up Hyalite and did a few stability tests, which did not dissuade us from skiing our line (<a href="https://youtu.be/io32nxnei0c"><strong>video</strong></a&gt;, <strong><a href="https://www.mtavalanche.com/images/17/divide-peak-pit-profile">snowpit<…;).</p>

<p>It did not freeze at the ridgetops last night and may not for a couple more days. The mountains around Cooke City and West Yellowstone have below freezing temperatures this morning, but will warm this afternoon. Across our forecast area the snow surface will get moist on sunny slopes and I expect to see pinwheels rolling off steep slopes along with a few small, wet loose avalanches (<strong><a href="https://www.mtavalanche.com/images/17/wet-loose-cooke-city">photo</a></…;, <strong><a href="https://www.mtavalanche.com/images/17/small-wet-loose-slides-beehive">p…;). While seemingly inconsequential, a small wet slide could push a skier off a cliff or into other high consequence terrain.</p>

<p>For today, the avalanche danger is <strong>LOW</strong>. But as stated above, be wary of wet avalanches on sunny slopes and dig to the ice crust before committing to avalanche terrain.</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>Last week, strong wind in the Bridger Range drifted snow into slabs below ridgelines and across mid-elevations&nbsp;along the edges of ridges and gullies (<strong><a href="https://www.mtavalanche.com/images/17/cross-loaded-terrain-saddle-peak"…;). Bridger Bowl Ski Patrol easily triggered these 1-3 foot thick slabs with explosives through last Friday. A couple warm days without load from snow and wind allowed these slabs to become stubborn and unlikely to break under the weight of a skier or rider. Although difficult to trigger, it is not impossible in steep terrain. Avoid drifts of snow on steep slopes or approach them with extra caution, especially where the consequences of a slide are high, like above cliffs (<strong><a href="https://www.mtavalanche.com/images/17/cross-loaded-terrain-saddle-peak"…;). Outside of the Bridger Range, small wind slabs near ridgelines are possible to trigger and should be approached with caution.</p>

<p>Aside from wind slabs, the snowpack is generally stable throughout the advisory area. There is a low possibility for snow from last week to slide on a layer of facets near the crust that formed during Thanksgiving. Dig 1-2 feet deep to assess the interface between the crust and last week’s snow before riding anything steep.</p>

<p>Aside from small and difficult to trigger wind slabs today, a generally stable snowpack exists and avalanche danger is <strong>LOW</strong>.</p>

<p>Today’s snow surface is next week’s weak layer. The current ridge of high pressure contributes to current&nbsp;good stability, but leaves future stability to question. Cold nights and clear skies create a strong temperature gradient at the surface of the snowpack. The snow surface is much colder than snow just a few inches below, which promotes a rapid transfer of moisture between snow crystals and grows them into angular, weak, sugary facets (<strong><a href="https://www.mtavalanche.com/images/17/small-faceted-grains">photo</a></…;). These facets will be buried by the next snowfall, and we will have to be cautious and carefully assess stability before venturing into avalanche terrain. Feathery, surface hoar crystals also formed during these cold, clear nights and will pose a threat when buried (<strong><a href="https://www.mtavalanche.com/images/17/surface-hoar-hyalite-0">photo</a>…;).</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>