20-21

<p>From Bozeman to West Yellowstone we have two overlapping avalanche concerns today: avalanches breaking under the newly wind-drifted snow and huge avalanches breaking on weak layers near the ground.&nbsp;</p>

<p>Fresh slabs of wind drifted snow will be easily triggered today. Yesterday we got reports of active wind loading across the northern ranges. With fresh snow overnight in the southern ranges and strong winds today new wind drifts are forming and older drifts will grow larger. While these wind slabs can break deep enough to be problematic all on their own, the big concern is that it may step down to the deeply buried weak layers and pull out the whole season’s snowpack.</p>

<p>Deep slab avalanches are our primary concern today. Over the last week we’ve seen deep avalanches in Hyalite (<a href="https://youtu.be/Ychm42ihtjk"><strong><u>video</u></strong></a&gt;, <a href="https://www.mtavalanche.com/images/21/natural-avalanche-blackmore-east-…;, <a href="https://www.mtavalanche.com/images/21/natural-deep-slab-flanders"><stro…;), Buck Ridge (<a href="https://youtu.be/65JO-4w4qXo"><strong><u>McAtee Basin video</u></strong></a>), and on Lone Peak (<a href="https://www.mtavalanche.com/images/21/lone-lake-cirque-avalanche"><stro…;). Yesterday we got reports of another very large avalanche near Big Sky, on Cedar Mountain (<a href="https://www.mtavalanche.com/images/21/deep-slab-avalanche-cedar-mountai…;). The likelihood of triggering one of these slides isn’t super high, but the recent natural and human triggered slides show it is clearly a possibility. If you do trigger one, it is likely to be unsurvivable. With weak snow at the ground on basically every slope, all steep slopes are suspect. Unfortunately, there is really no way to effectively assess these weak layers. Avoidance is the only safe way to deal with this deep slab problem. Stay off of, and out from under, slopes steeper than 30 degrees to keep from waking the sleeping dragon at the base of the snowpack.</p>

<p>With deep, dangerous avalanches possible the avalanche danger is rated MODERATE.</p>

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<p>In Cooke City, avalanches on wind loaded slopes are our primary concern. During the last snow and wind event (Monday into Tuesday), a number of wind slab avalanches and cornices broke (<a href="https://youtu.be/-aLItsHjWLI"><strong><u>video</u></strong></a&gt;). These slides are becoming more difficult to trigger, but I still don’t trust steep, windloaded slopes. Also, keep in the back of your mind the possibility of weak snow at the ground. It isn’t widespread, but could catch you off guard with a much deeper, wider avalanche. For today the avalanche danger is rated MODERATE on all slopes.&nbsp;</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><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>