20-21

<p>Since last Wednesday the mountains near Bozeman and Big Sky got 3-4 feet of snow equal to 2.5-3.5” of snow water equivalent (SWE), which is more than what they got in all of January (and most of December). Yesterday there were natural avalanches on the west side of Saddle Peak (<strong><a href="https://www.mtavalanche.com/node/24129">info</a></strong&gt;), and another on Cedar Mountain (<strong><a href="https://www.mtavalanche.com/node/24135">photo</a></strong&gt;). Skiers in Beehive triggered a small test slope that produced a relatively very large slab avalanche (<strong><a href="https://www.mtavalanche.com/node/24127">photos</a></strong&gt;). Ski patrols at the Yellowstone Club and Big Sky triggered very large avalanches on deep buried weak layers, and saw wide natural avalanches on road cuts (<strong><a href="https://www.mtavalanche.com/node/24136">photos</a></strong&gt;). The list of avalanches, and widespread collapsing over the last four days is extensive (<a href="https://www.mtavalanche.com/weather/wx-avalanche-log">weather and avalanche log</a>). Many avalanches broke deep and wide on sugary, buried weak layers.</p>

<p>Yesterday Doug looked at the snowpack outside of Bridger Bowl’s boundary. As he explains in his <strong><a href="https://www.youtube.com/watch?v=FeU_7Q_hhDI&amp;list=PLXu5151nmAvQDzKmH…; even when it stops snowing we will be still able to trigger large avalanches for days. Wind is continuing to drift recent low-density snow into thick slabs on top of a very weak snowpack. Today very dangerous avalanche conditions exist, and danger is HIGH on wind-loaded slopes and CONSIDERABLE on all other steep slopes. Avoid travel on and underneath slopes steeper than 30 degrees.</p>

<p>Since Wednesday the mountains near Cooke City received 3-4 feet of snow equal to 2.9” of SWE. The last couple days moderate to strong west-northwest wind drifted the snow into thicker slabs. These can avalanche and will be large enough to bury or injure a person, and could break deeper on buried weak layers (<a href="https://www.youtube.com/watch?v=u1BY8bb327k&amp;list=PLXu5151nmAvQDzKmH…; from Friday</strong></u>). Yesterday a skier saw natural avalanches on the drive through Yellowstone Park (<strong><a href="https://www.mtavalanche.com/node/24139">photos</a></strong&gt;). On Friday a skier triggered and was partially buried in an avalanche near Hayden Creek (<a href="https://www.mtavalanche.com/node/24075"><strong>photo and details</strong></a>). This recent heavy snowfall creates dangerous avalanche conditions. With a few more inches of snow and continued wind today natural and human triggered avalanches are likely, especially on wind loaded slopes. The avalanche danger is HIGH on wind-loaded slopes and CONSIDERABLE on all other slopes. Avoid travel on and underneath slopes steeper than 30 degrees</p>

<p>Since Wednesday the mountains near West Yellowstone received 2 feet of snow equal to 2.1” SWE, with no measurable snow since yesterday morning. Human triggered avalanches are likely and will be large enough to kill. On Saturday near Lionhead Ridge a snowmobiler triggered an avalanche that broke wide, and luckily nobody was caught (<a href="https://www.mtavalanche.com/node/24111"><strong>photo</strong></a&gt;). Weak, sugary snow buried 3-4 feet deep is slow to gain strength, and it can collapse under the weight of a person, and break wide across slopes (<a href="https://youtu.be/CI0HFvtLrf4"><strong>Lionhead video</strong></a>). Today, very careful route finding and conservative terrain selection are essential. Avalanche danger is CONSIDERABLE.</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>