20-21

<p>Strong, swirly winds at all elevations and 4 days of snowfall spiked the avalanche danger. Over 2 feet of snow fell (2.2” <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</u></a><u> </u>- SWE) and yesterday there were many natural avalanches on wind-loaded slopes and a couple skier triggered slides, one breaking hundreds of feet wide (<a href="https://www.mtavalanche.com/node/23352"><strong><u>details</u></strong>…;).&nbsp; All were avalanching at the interface between the old and new snow (1-3’ deep). Ian and I are in Cooke City and saw a few of these and noted the instability in our snowpits (<a href="https://youtu.be/bHZazXX4EXM"><strong><u>video</u></strong></a&gt;). For today, check out the 5 entries for <a href="https://www.mtavalanche.com/avalanche-activity"><strong><u>avalanche activity</u></strong></a> and look at the <a href="https://www.mtavalanche.com/photos"><strong><u>photos page</u></strong></a> to get a handle on the problem. Today is better stability than yesterday, but triggering slides is still likely on steep slopes, especially wind-loaded, and the danger is rated CONSIDERABLE. I do not expect many <em>natural </em>avalanches today, but skier and sledder triggered ones are a serious threat. Travel on at a time in avalanche runout zones and don’t let beautiful, sunny skies paint a false, rosy picture.</p>

<p>Lionhead received an inch of snow yesterday. Faceted, sugary grains of weak snow underlie the bottom 2 feet of a 3-foot snowpack. Snowfall on Sunday triggered natural avalanches and Dave and I were able to trigger 2 from low angled terrain 30’ and 75’ away (<a href="https://www.youtube.com/watch?v=u0Wqce1UvKY&amp;list=PLXu5151nmAvQDzKmH…;, <a href="https://mtavalanche.com/images/20/remote-triggered-avalanche-2-ski-hill…;, <a href="https://mtavalanche.com/images/20/small-snowmobile-triggered-slides-cab…;)</u></strong>. The snowfall has ended, but windblown snow is adding to the instability. Cracking, collapsing (whumpfs), and recent avalanches are signs to stay clear of steep slopes. Triggering slides on wind-loaded terrain is likely and the avalanche danger is rated CONSIDERABLE on wind-loaded slopes and MODERATE on all others.&nbsp;</p>

<p>The Bridger, northern Gallatin and northern Madison Ranges finally got snow: 5-7” (.5-.7” SWE). This was the largest storm since the season opener on October 11. Accompanying the snow was strong westerly wind. Avalanches are likely to be triggered on wind-loaded slopes and possible on steep, non-windloaded ones. The snowpack is weak and unstable. Sugary facets at the bottom ⅔ of the snowpack will struggle to support the new windblown snow (<a href="https://mtavalanche.com/images/20/wind-slabs-triggered-bridger-patrol">…;). For today, the avalanche danger is rated CONSIDERABLE on wind-loaded slopes and MODERATE on all others. A moderate danger is not a green light, it literally means it is possible to trigger slides.</p>

<p>The southern Madison and southern Gallatin Ranges got 1-2” yesterday with strong, gusty, west wind. The snowpack has a foundation of weak, sugary facets, but without significant loading since Friday its stability is improving. Dave and Alex rode into Taylor Fork on Monday and found poor snow structure and saw avalanche debris and crowns from Friday’s storm (<a href="https://www.youtube.com/watch?v=IUb9ub26y1o"><strong><u>video</u></stro…;, </strong><a href="https://mtavalanche.com/images/20/natural-avalanche-sunlight-basin-1"><…;, </strong><a href="https://mtavalanche.com/node/23302"><strong><u>avalanche activity</u></strong></a>). Avalanches were breaking on the loose facets in the lower part of the snowpack and when snowfall resumes I expect to see more slides. Since the snowpack is weak and triggering avalanches is possible, the 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>