Snowpack and Avalanche Discussion
<p>Very dangerous avalanche conditions exist in the Bridger Range and the mountains around Cooke City. Human-triggered and natural avalanches are likely. Give avalanche terrain a wide berth, by staying off and out from under any slope steeper than 30 degrees. The Bridger Range has received over 30” of snow, equal to 3.2” of <a href="https://www.mtavalanche.com/taxonomy/term/451"><span>snow water equivalent</span></a> (SWE) since Saturday morning. The mountains near Cooke City received 14” of snow equal to 0.9” SWE, primarily in the last 24 hours. Winds gusting to 55 mph are drifting snow and adding additional load to slopes at all elevations. Avalanches within the new and wind-drifted snow will be dangerous. Slides could break on buried weak layers resulting in larger avalanches that run well into the flats below.</p>
<p>As we discussed in our video from the Throne in the Bridger Range yesterday, you don’t have to stay out of the backcountry, but you do need to stay away from all avalanche terrain (<a href="https://www.youtube.com/watch?v=ncycT237y64"><strong><span>video</span>…;
<p>The avalanche danger is HIGH on all slopes.</p>
<p>The Gallatin and Madison Ranges received 10” of snow (0.9” of SWE) closer to West Yellowstone and 17” of snow (0.8-1.3” of SWE) near Big Sky and in Hyalite Canyon. Strong winds are building unstable drifts at all elevations and aspects. Continuing snowfall will load slopes to their breaking point. Human-triggered avalanches are likely within the new and wind-drifted snow. These will be enough to capture, carry and bury skiers or riders. Larger slides breaking on weak layers buried in the upper few feet of the snowpack are possible. Cautious route-finding, careful snowpack evaluation and conservative decision-making are essential.</p>
<p>The avalanche danger is CONSIDERABLE on all slopes.</p>
<p>The Lionhead area received 7” of snow in the last 48 hours (0.6” SWE). Winds gusting to 55 mph are drifting and loading this snow onto slopes that could avalanche today. Avalanches within the drifted snow will be large enough to carry a rider or skier. Turn back from steep terrain if you observe signs of instability related to recent wind-loading, such as fresh avalanche activity, newly formed pillows of snow, or cracks shooting out from your sled or skis. Any of these signs should turn us back toward lower-angle slopes or non-wind-loaded areas. A rider-triggered slide in Airplane Bowl five days ago indicates the most likely type of avalanche today (<a href="https://www.mtavalanche.com/node/28166"><strong><span>details and photo</span></strong></a>). Deeper avalanches are unlikely but dig a quick snowpit and test for instability in the upper three feet of the snowpack before riding or skiing a steep slope.</p>
<p>The avalanche danger is MODERATE on all slopes.</p>
<p>Expect the avalanche danger to rise if snowfall today if snowfall intensifies.</p>
<p>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></p>
<p>The Centennial Range received 5” of snow in the last 48 hours (0.4” SWE). Winds gusting to 55 mph are drifting and loading this snow onto slopes that could avalanche today. Turn back from steep terrain if you observe signs of instability related to recent wind-loading, such as fresh avalanche activity, newly formed pillows of snow, or cracks shooting out from your sled or skis. Deeper avalanches are unlikely but dig a quick snowpit and test for instability in the upper three feet of the snowpack before riding or skiing a steep slope.</p>
