17-18

<p>At this point, a fresh layer of snow this early in the season is no surprise. The mountains have 3-4 feet of snow near Bozeman and Cooke City, and 2-3 feet near Big Sky and West Yellowstone. People have been skiing, ice climbing and snowmobiling, and have observed and triggered avalanches.</p>

<p>New snow last night and wind today create unstable conditions on wind-loaded slopes. Avoid avalanche terrain if you see obvious sign of instability like cracking, collapsing, and recent avalanches. I observed similar conditions at Bridger on Tuesday (<strong><a href="https://youtu.be/4TJFOP7D1y8">video</a></strong&gt;), and Doug saw drifting in Hyalite yesterday (<strong><a href="https://youtu.be/4eBF2YWsDOc">video</a></strong&gt;). On Tuesday, I easily triggered a small wind slab north of Bridger Bowl, intentionally from a safe spot. It was fairly small, but would have been inescapable, and ran through a narrow, steep, rocky chute. Avoid wind-loaded slopes, likely found near ridgelines, and assess steep terrain for consequences of even a small slide.</p>

<p>Last night’s snow fell on weak layers and crusts that formed over the last couple days (<strong><a href="https://www.mtavalanche.com/images/17/surface-hoar-near-bridger-bowl">p…;, <strong><a href="https://www.mtavalanche.com/images/17/surface-hoar-hyalite">photo</a></…;). Dig down a couple feet to assess the stability of the new snow before riding in steep terrain. If the new snow easily slides or collapses, avoid similar slopes. Stability has been generally good on non-wind loaded slopes. However, it is still early and data is limited. Near Cooke City, riders observed avalanches breaking deep in the snowpack (<strong><a href="https://www.mtavalanche.com/images/17/avalanche-crown-butte-0">photo</a…;), which shows deeper slides are possible on slopes that hold snow from September and October. If you plan to ski or ride in avalanche terrain, I suggest to dig multiple snowpits in similar terrain to where you plan to ride and assess the stability of deeper layers (<strong><a href="https://youtu.be/im0A8Wk-NsE">video</a></strong&gt;).</p>

<p>We will begin issuing daily avalanche advisories and danger ratings when the mountains get more snow. Our field data is currently limited. Besides our own field days we rely on others to help us form a picture of what’s happening across our forecast area. 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>