22-23
snowpack is becoming stronger
I am finding very solid snowpack in most areas. We dug one pit yesterday that exhibited two weak layers in the top 35cm and one near the ground. This was a wind loaded slope with HN 230cm. CT test did not fail. No evidence of surface hoar at this location. 9100 feet on a NE aspect.
At lower elevations I found evidence of surface hoar forming, but not necessarily on the snow, see photo.
We are entering a warming trend, which is generally healthy for the snowpack. The conditions are right for surface hoar development; however, I am only finding very isolated evidence of this. Something to keep an eye out for.
We have several weak layers in the snowpack that could fail causing an avalanche, likely a large deadly avalanche. It's hard to find places that exhibit reactive test results, but the evidence is in recently human triggered avalanches. We are not getting a ton of new snow and together with the mild temperatures this will create a strong snowpack over time. The places to watch out for are shallower snowpack areas where the persistent weak layer is easier to trigger.
GNFAC Avalanche Forecast for Sun Jan 8, 2023
<p><span><span><span><span><span><span>A person can trigger avalanches that break on weak layers buried 1-4 feet deep, or avalanches that involve recently wind-drifted snow. Yesterday, on Buck Ridge near Big Sky a snowboarder triggered a small avalanche on a wind-loaded slope and was partially buried to their waist (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/snowboarder-caught-small-slide"><…;), and Skiers in the northern Bridger Range saw a recent large natural avalanche that broke 1-2 feet deep and 100 feet wide (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/snowboarder-caught-small-slide"><…;). Two days ago, a very large avalanche on Saddle Peak broke 550 feet wide and almost 2 feet deep on a buried weak layer (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/crown-close-saddle-peak"><span><s… of crown up close</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). It caught and partially buried a person who was hitting a jump in the runout zone (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27536"><span><span><span><strong><span… and details</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Carefully assess the snowpack for buried weak layers and avoid steep slopes where you suspect they exist. Buried weak layers are not consistently showing instability in our snowpack tests, but avalanche activity over the past week is a clear sign that large avalanches can be triggered. The fatal avalanche last weekend near Cooke City should provide good motivation to take buried weak layers seriously (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/accident/22/12/31"><span><span><span><stron… report</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Be extra cautious of wind-loaded slopes and slopes where snow depth is variable where a large avalanche may be triggered from a relatively shallow spot. Look for cracks across the snow surface around your skis or sled as a sign that recently drifted snow remains unstable. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Today, human-triggered avalanches are possible and the avalanche danger is MODERATE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>In Island Park a person can trigger avalanches that break deep and wide on buried weak layers, or avalanches that involve recently wind-drifted snow. Carefully assess the snowpack for buried weak layers and avoid steep slopes where you suspect they exist. If snow starts to accumulate early today, fresh drifts may form that could avalanche. Look for cracks across the snow surface around your skis or sled as a sign that drifted snow is unstable.</span></span></span></span></span></span></p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
Close up of the crown of the avalanche on Saddle Peak that broke on Friday 01/6/23. 18-24" deep.
Forecast link: GNFAC Avalanche Forecast for Sun Jan 8, 2023GNFAC Avalanche Forecast for Mon Jan 9, 2023
Snowboarder triggered/caught small slide on Buck Ridge
Location: 45.165, -111.35808 (onX)
Elevation: ~9,200 feet
While riding a small NNE facing slope near the trail on Buck Ridge, a snowboarder triggered and followed a cornice slide that propagated approximately 75 feet and slid about 20' vertical. The one rider was caught and carried approx. 10' and ended up buried upright, waist deep with no injuries.
From obs: "While riding a small NNE facing slope near the trail on Buck Ridge, a snowboarder triggered and followed a cornice slide that propagated approximately 75 feet and slid about 20' vertical. The one rider was caught and carried approx. 10' and ended up buried upright, waist deep with no injuries."
From obs: "While riding a small NNE facing slope near the trail on Buck Ridge, a snowboarder triggered and followed a cornice slide that propagated approximately 75 feet and slid about 20' vertical. The one rider was caught and carried approx. 10' and ended up buried upright, waist deep with no injuries."
Natural Avalanche near Fairy Lake
From IG 1/7/23: "Natural slide in avalanche bowl up in fairy lake today."