22-23
Surface Hoar buried 1 foot deep
We had good visibility and rode to Lulu to look at an ava that was triggered yesterday, a small cornice collapse. The one on Chimney Rock (triggered 2 days ago) was not big, but more indicative of weak layers at the ground. Chimney was 2 slides side-by-side, mid-slope, that likely went at the same time. These likely broke on facets near the ground. The snowpack was thin there. We then rode to Wolverine and Abundance. We saw a new snow slide on Wolverine in the deep cleft on the face. We dug on the shoulder of Abundance (HS 200+) and did not get anything remarkable in our stability test. We then rode to Henderson Bench. There was one small slide off the Henderson ridge by the radio hut. We dug off the bench and got a surprising ECTP 11 on surface hoar buried 30 cm under. Crystals were not big (2-4mm) and you could not see it in the pit wall, but the ECT sure popped it out.
A rider triggered a small avalanche in First Yellowmule on Sunday that broke approximately 6-8" deep, 60' wide, and ran 20'. Photo: D. Kristensen
GNFAC Avalanche Forecast for Tue Jan 10, 2023
<p><span>The southern ranges of the advisory area have received 7-9” of new snow in the last 48 hours. With snowfall and wind decreasing this morning, I do not expect to see natural avalanches during the day, one of the thresholds for considerable danger. However, we are on edge with large, human-triggered avalanches being a distinct possibility. In the last three days near Cooke City, a skier was caught and carried in an avalanche in the Sheep Creek drainage, snowmobilers triggered avalanches near Chimney Rock on Henderson Mountain and near Lulu Pass (</span><a href="https://www.mtavalanche.com/node/27569"><strong><span>photo and details</span></strong></a><span>, </span><a href="https://www.mtavalanche.com/avalanche-activity"><strong><span>avalanche activity list</span></strong></a><span>). Ten days ago, there was a tragic avalanche fatality on Crown Butte </span>(<a href="https://www.mtavalanche.com/accident/22/12/31"><strong><span>accident report</span></strong></a><span>, </span><a href="https://www.youtube.com/watch?v=zjGCqBikpRw&list=PLXu5151nmAvTi1DBS…;). </span></p>
<p><span>Avalanches breaking below the new snow and recent drifts are most likely, but weak layers buried throughout the snowpack, including sugary snow near the ground, make possible a full spectrum of avalanches from relatively small to very large. Watch my </span><a href="https://www.youtube.com/watch?v=ECi646U0Rtg"><strong><span>video</span>…; from the Taylor Fork in which I point out these layers</span><span>. </span></p>
<p><span>The </span><a href="https://www.mtavalanche.com/avalanche-activity"><strong><span>avalanche activity list</span></strong></a><span> is an excellent place to start when considering terrain choices today. Avoid slopes steeper than 30 degrees if you observe recent avalanche activity, evidence of drifting, cracks shooting from the skis or board, whumphs, or get unstable test results. </span></p>
<p><span>The avalanche danger is MODERATE.</span></p>
<p>Yesterday, the northern portions of the advisory area received 1-3” of new snow and experienced strong winds. Avalanches failing within recent drifts of snow and on persistent weak layers buried deeper in the snowpack are possible. On Sunday, a snowmobiler triggered a small avalanche on a wind-loaded slope in First Yellowmule at Buck Ridge (<a href="https://www.mtavalanche.com/node/27587"><strong><span>details</span></s…;) and a snowboarder remotely triggered an avalanche in the backcountry outside of Big Sky Resort from 20 feet away (<a href="https://www.mtavalanche.com/node/27582"><strong><span>details</span></s…;). On Saturday, an avalanche caught and partially buried a snowboarder on a wind-loaded slope at Buck Ridge (<a href="https://www.mtavalanche.com/images/23/snowboarder-caught-small-slide"><… and photo</span></strong></a>). Skiers in the northern Bridger Range saw a recent natural avalanche that failed deep within the snowpack (<a href="https://www.mtavalanche.com/node/27555"><strong><span>photo</span></str…;). A near miss on Saddle Peak in the Bridger Range that broke 550 feet wide and almost 2 feet deep on a buried weak layer rounds out the avalanche activity from the last four days (<a href="https://www.mtavalanche.com/node/27536"><strong><span>photos and details</span></strong></a>).</p>
<p>As Alex and I suggested in our <a href="https://www.youtube.com/watch?v=D38XfiTnFwU&list=PLXu5151nmAvTi1DBS…; from the Bridger Range Sunday, perform a careful snowpack assessment looking for instability related to buried weak layers before considering going into avalanche terrain. Choose slopes without terrain traps like cliffs, trees or rocks and follow safe travel protocols.</p>
<p>The avalanche danger is MODERATE.</p>
<p><span>Please share avalanche, snowpack or weather observations via our<a href="https://www.mtavalanche.com/node/add/snow_obs"><span> </span></a><a href="https://www.mtavalanche.com/node/add/snow_obs"><strong><span>website</s…;, email (<strong>mtavalanche@gmail.com</strong>), phone (406-587-6984), or Instagram (#gnfacobs). <span><span> </span></span></span></p>
<p><span>The Centennial Range received 7” of snow in the last 48 hours. Avalanches are most likely to break below the new and wind-drifted snow but could break deeper in the snowpack on buried weak layers. Slopes with drifts from yesterday’s strong winds are the most suspect. Evaluate the snow and terrain carefully to identify concerns related to wind-drifted snow and buried weak layers.</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.
TONIGHT, Tuesday, January 10th, 6PM, Women’s Specific Avalanche Awareness + Beacon Practice at Story Mill Park in Bozeman. Free.
Snowmobile Triggered Avalanche, First Yellowmule
A rider triggered a small slide in First Yellowmule on Sunday. Broke 6 -8" deep, 60' wide, and ran 20'. North face, about 37 degrees steepness.