23-24

<p>The sun will break out from behind the clouds today, and the danger of wet snow avalanches will rise as the snow from recent storms starts sliding on the underlying crust. The size and frequency of these avalanches depend on how much snow fell during the last storm (Over 2 feet in the Bridger Range, 12” around Big Sky and 4-7” everywhere else), how warm the temperatures get, whether lingering clouds shade slopes and if wind cools the snow surface. Though there is uncertainty about the timing and extent of wet snow avalanches today, recognizing the signs of increasing danger is relatively simple. A wet snow surface, cinnamon roll-like snowballs shedding from steep rocky areas and small natural slides indicate that the danger is increasing. Have a safe exit plan, as conditions can change quickly. Shift to cooler aspects or head home as this transition occurs.</p>

<p>Dry slab activity within the new and wind-drifted snow has decreased since this weekend (<a href="https://www.mtavalanche.com/avalanche-activity"><strong><span>avalanche activity log</span></strong></a>). However, dry slab avalanches within the recent storm snow are the primary concern before the warm-up and throughout the day at high elevations and shady north-facing slopes. Our recent videos from <a href="https://youtu.be/iO3EWqb0oqg?feature=shared"><strong><span>The Ramp</span></strong></a> and <a href="https://youtu.be/Fjo1jg8p49M?feature=shared"><strong><span>The Throne</span></strong></a> demonstrate digging down until you hit the thick upper ice crust to test for instability in the top few feet of the snowpack before committing to avalanche terrain. Selecting non-wind-loaded terrain is a good way to reduce the risk of triggering a slide.</p>

<p>While a low-probability event, the structure to produce very large avalanches remains present, especially on steep high-elevation slopes and those that remained cool through the recent warm-ups. If seeking this type of terrain, recognize the residual risk of triggering an unsurvivable avalanche and follow safe travel protocols to limit the number of people who might get caught. Slopes that went through recent melt-freeze cycles or less steep, small slopes are safer.</p>

<p>The danger is rated MODERATE and will rise to CONSIDERABLE for wet snow avalanches.</p>

<p><span><span><span><span><span><span>The forecasted clouds and wind will keep the </span></span></span></span></span></span><span><span><span><span><span><u><span><span>wet snow</span></span></u></span></span></span></span></span><span><span><span><span><span><span> avalanche danger at bay for one more day. Although I do not expect sun today, </span></span></span></span></span></span><span><span><span><strong><span><span>if </span></span></strong></span></span></span><span><span><span><span><span><span>it shines, the snow surface will melt quickly and avalanche danger will rise. Stay out of avalanche terrain once you start seeing roller balls or start sinking into wet snow.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The </span></span></span></span></span></span><span><span><span><span><span><u><span><span>dry snow</span></span></u></span></span></span></span></span><span><span><span><span><span><span> avalanche danger is a larger concern, especially on wind-loaded slopes. Over 2 feet of snow fell in the Bridger Range over the weekend with 12” around Big Sky and 4-7” everywhere else. On Sunday, skiers triggered </span></span></span></span></span></span><a href="https://www.mtavalanche.com/avalanche-activity"><span><span><span><stro… avalanches in the Bridger Range</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> in the new snow. Both Alex and Dave made videos of the instability to look out for </span></span></span></span></span></span><a href="https://youtu.be/iO3EWqb0oqg?feature=shared"><span><span><span><strong>… Ramp (video)</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> and </span></span></span></span></span></span><a href="https://youtu.be/Fjo1jg8p49M?feature=shared"><span><span><span><strong>… Throne (video)</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>. This activity has subsided, but the current wind will keep the possibility of triggering slides alive. Wind is loading slopes at many elevations so be careful in gullies and near ridgelines where drifts can be thick. This new snow is sitting on a hard ice crust in many areas which may help avalanches propagate wide.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Deeper in the snowpack near the ground is a layer of facets that blanket our forecast area. This layer is weak and could avalanche, especially on higher elevation slopes that did not experience melting last week. We consider this risk low probability, high consequence. If getting up high is your jam today, then dig, assess and be aware of the possibility of a large avalanche.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The danger is rated MODERATE throughout our forecast area.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near Bozeman and Big Sky the snow that fell over the weekend creates heightened avalanche conditions and you can trigger avalanches that break within or below this snow. This afternoon the danger will increase due to sunshine and temperatures above freezing making large wet loose avalanches likely.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Over the weekend the Bridger Range got over 2 feet of snow equal to 2.5-3.0” of snow water equivalent (SWE), and Big Sky and Hyalite got 7-12” equal to 0.7-1.2” SWE. Yesterday in the Bridgers, Dave and I measured the snow and investigated stability at </span></span></span></span></span></span><a href="https://youtu.be/iO3EWqb0oqg?feature=shared"><span><span><span><strong>… Ramp (video)</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> and </span></span></span></span></span></span><a href="https://youtu.be/Fjo1jg8p49M?feature=shared"><span><span><span><strong>… Throne (video)</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, and there were many skier triggered slides that broke within the new snow throughout the range (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/24/skier-triggered-slab-wolverine"><… photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31775"><span><span><span><strong><span… photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31777"><span><span><span><strong><span… Lake photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31789"><span><span><span><strong><span…. Bridgers photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/24/skier-triggered-avalanche-banana-… Peak</span></span></u></span></strong></span></span></span><span><span><span><span><span><u><span><span> </span></span></u></span></span></span></span></span><span><span><span><strong><span><u><span><span>photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>).&nbsp;</span></span></span></span></span></span><span><span><span><span><span><span>Similar avalanches can be triggered today. </span></span></span></span></span></span><span><span><span><span><span><span>Although these types of instabilities typically heal quickly, today you should steer clear of fresh drifts and carefully assess the potential for the new snow to slide. Choose smaller slopes and slopes without cliffs, trees, rocks or gullies that would increase the chances of being injured or killed in any size slide.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>When the sun comes out stability will quickly decrease and make wet avalanches that can run long distances. These slides could become large where more snow fell, and even a small wet slide will easily knock you over or carry you down a steep slope. Plan to be off of and out from below steep slopes before the recent snow becomes moist or wet. A sticky snow surface is a sign to find shadier or lower angle slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Avalanches breaking on deeper weak layers are unlikely, but not out of the question on higher, shady slopes that didn’t get as wet last week. Dig down a few feet to check for buried weak layers before getting onto steep slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today the avalanche danger starts at MODERATE and will increase to CONSIDERABLE for wet snow avalanches later in the day.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near West Yellowstone, Island Park and Cooke City less snow over the weekend and more clouds today will minimize the threat of wet snow avalanches compared to other areas. Over the weekend these mountains got 4-7” of snow equal to 0.4-0.7” SWE. You can trigger avalanches where new snow is drifted into thicker slabs, and wet loose avalanches will be possible if the sun comes out (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=Qcwz2QLOKxE&amp;list=PLXu5151nmAvSH326z…;). Wind slabs or wet loose avalanches could easily slide on the hard melt-freeze crust below.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Watch for cracking across the snow surface as a sign unstable drifts exist, and if the snow surface gets moist expect wet loose avalanches. Choose slopes without trees, cliffs or other terrain traps that would increase the chances of being injured in even a small slide. Deeper avalanches are unlikely, but not impossible. If you are riding steep, consequential slopes it is a good idea to dig down a few feet to look for weak layers and assess snow stability. Avalanche danger is MODERATE near Cooke City, West Yellowstone, Island Park, and in the southern Madison and southern Gallatin ranges.</span></span></span></span></span></span></p>