20-21

<p>Over the last 24 hours extreme southwest winds drifted 1-2 feet of recent snow into thick, unstable slabs (<strong><a href="https://www.mtavalanche.com/images/21/snow-transport-lone-mountain">pho… of wind transport</a></strong>). Today riders or skiers can trigger avalanches of wind-drifted snow 1-3 feet thick. These drifts exist along ridgelines as well as less common locations, like lower on slopes or in the trees, due to the abnormally strong wind speeds. Today’s new snow and wind will add weight and may hide visual evidence of yesterday’s drifts. Avoid steep slopes that are commonly wind loaded, like below cornices and along ridgelines. Feel for changes in snow hardness under your sled or skis, or dig and probe to feel for denser wind slabs under today’s snow.</p>

<p>Additionally, there is a chance avalanches can break wide on a thin weak layer under last week’s snow. We have found this weak layer to be unstable in some of our snowpits, but not all, near Cooke City (<a href="https://www.youtube.com/watch?v=CZ27CVuKWuA"><strong>Cooke video</strong></a>) and Buck Ridge (<a href="https://www.youtube.com/watch?v=JZ1rnPsoIIg&amp;list=PLXu5151nmAvQDzKmH…;, <a href="https://www.youtube.com/watch?v=zCKlHstJTqc&amp;list=PLXu5151nmAvQDzKmH…;). Dig a quick pit to check for this layer before riding steep slopes (<strong><a href="https://www.youtube.com/watch?v=sqn0KFZqXYs&amp;list=PLXu5151nmAvQDzKmH…;

<p>On Saturday near Mt. Blackmore a skier remotely triggered an 8-10 foot deep avalanche that broke on weak, sugary snow near the ground (<a href="https://www.mtavalanche.com/node/24732"><strong>photos and details</strong></a>), and skiers reported a recent natural deep slab in Flanders Creek (<a href="https://www.mtavalanche.com/images/21/natural-deep-slab-near-flanders">…;). Also, a snowmobiler triggered slide near Buck Ridge broke on weak snow near the ground on a slope that previously slid on this layer (<strong><a href="https://www.mtavalanche.com/node/24748">photo and details</a></strong>). These avalanches are the first to break on this deep weak layer since February. The likelihood is low for triggering a deep slab avalanche, but recent slides are a sign that the added weight from last week’s snow and wind-loading has made it possible to trigger a deep slab.</p>

<p>Today, on wind-loaded slopes human triggered avalanches are likely and avalanche danger is CONSIDERABLE. On non-wind loaded slopes avalanche danger is MODERATE.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>