21-22

<p>The snowpack is generally stable other than small, surface-level instabilities created by yesterday’s 1-3” of new snow. Yesterday, skiers noted relatively small and harmless slabs up to 5” deep predictably breaking near ridgelines where winds formed small drifts. Today, these could be a problem in steep or technical terrain where they could knock you off your feet or sled but would be unlikely to bury a skier or rider. The danger associated with these small avalanches will increase if snowfall intensifies this afternoon.</p>

<p>Beyond these superficial instabilities, keep the fundamentals in mind. We have a layered snowpack and as Ian found in the Flanders drainage on Tuesday, there are isolated areas of instability in a sea of overall stability (<a href="https://youtu.be/-ha6ugs0Wgs"><strong>video</strong></a&gt;). Assess the snowpack with a pit and a quick stability test to make a <em>slope-scale </em>forecast before entering avalanche terrain. If you are surprised by less stable results, dial your objectives back as Ian did in Hyalite.</p>

<p>Finally, we have a new weak layer buried under a few inches of snow in the Southern Madison and Southern Gallatin Ranges and the Lionhead and Cooke City areas that will likely become a problem as it gets buried deeper. Ian found this stripe of feathery surface hoar buried in the Taylor Fork yesterday, Alex and Doug saw it in Cooke City and at Lionhead earlier in the week and skiers and riders have sent in observations confirming that this layer is widespread (<a href="https://www.youtube.com/watch?v=zlREIgIkphs"><strong>Taylor Fork video</strong></a>, <a href="http://www.mtavalanche.com/images/22/buried-surface-hoar-near-cooke-cit… City photo</strong></a>/ <a href="https://youtu.be/FOJv3cTQ8rs"><strong>video</strong></a&gt;, <a href="https://youtu.be/g7Pl9-raU7g"><strong>Lionhead video</strong></a>). Follow along for more information as conditions evolve.</p>

<p>Today, human-triggered avalanches breaking deeper than the thin layer of new snow are unlikely and the danger is rated LOW.</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>

<p>A few inches of new snow is not enough weight to adversely affect the stability of the snowpack. Wind at the ridgeline may create thin pockets of drifted snow, but these won’t be deep or widespread. Yesterday, Ian and his partner toured up Flanders drainage in Hyalite. They dug a snowpit on a slope adjacent to where they were planning to ski and got unstable test results, which is not what they were expecting (<a href="https://youtu.be/-ha6ugs0Wgs"><strong><u>video</u></strong></a&gt;). He said, “I’d much rather get surprised in my snowpit than surprised by an avalanche.” This is why we dig, even when avalanches are unlikely. Knowing what’s under our feet is critical information.&nbsp;</p>

<p>South of Big Sky to West Yellowstone and Cooke City, the snowpack is stable but we just buried a new weak layer, a future problem. Feathery crystals of surface hoar that formed during clear nights (<a href="http://www.mtavalanche.com/images/22/west-yellowstone-surface-hoar"><st…;) are now 1-3” under the snow surface. Alex is in Cooke City and confirmed they are now buried and preserved (<a href="http://www.mtavalanche.com/images/22/buried-surface-hoar-near-cooke-cit…;, <a href="https://youtu.be/FOJv3cTQ8rs"><strong><u>video</u></strong></a&gt;). Yesterday, I found them under the surface in Lionhead near West Yellowstone (<a href="https://youtu.be/g7Pl9-raU7g"><strong><u>video</u></strong></a&gt;). Their distribution is widespread at most elevations and aspects in the southern mountains. This specific weak layer is resistant to strengthening and can remain a problem for a month or more. I expect avalanches on this layer once we get more snow, but not today.</p>

<p>The basics of avalanche safety never get old, they keep us trained and focused. Carry rescue gear, practice with it, only expose one person at a time on a slope and dig and test before committing to avalanche terrain. Today the avalanche danger is rated LOW on all slopes in the forecast area since avalanches are unlikely.&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>