19-20

<p>Triggering a large avalanche is likely today, particularly on windloaded slopes near ridgelines. While snowfall tapered off yesterday near Bozeman and Big Sky, strong west winds continued with gusts up to 40 mph. With around a foot of recent snow (1-1.5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a>) available for transport, dense drifts of wind deposited snow continued to build and get deeper. This continued loading means the snowpack hasn’t had a chance to catch it’s breath yet. Avoid steep slopes and give it time to adjust. Slides will break in the new snow, but could also break on weak layers deeper in the snowpack if you get unlucky. The avalanche danger is rated CONSIDERABLE today.</p>

<p>The southern mountains got a little less snow (~1” SWE), but it fell onto a weaker snowpack. Triggering large avalanche breaking near the ground is the primary concern. On Wednesday, Doug and Dave found the weak, sugary snow at the ground struggling to support the new snow at Bacon Rind (<strong><a href="https://youtu.be/Ww-vCQEg-wA">video</a></strong&gt;). With these widespread weak layers, you can trigger an avalanche from flat ground beneath a steep slope. Give steep slopes and the <a href="https://avalanche.org/avalanche-encyclopedia/runout-zone/">runout zones</a> beneath them a wide berth while the snowpack adjusts to this new load. For today, the avalanche danger is rated CONSIDERABLE on all slopes.</p>

<p>The mountains near Cooke City have multiple avalanche concerns, but for today the strategy to deal with all of them is simple – avoid steep slopes. While this storm generally brought a foot of new snow (1” of SWE) to the mountains around Cooke City, yesterday I found some areas with closer to two feet of new snow with deeper drifts. These drifts were cracking and a number of small avalanches were seen in the new snow (<strong><a href="https://www.mtavalanche.com/node/21414">details</a></strong&gt;). If that’s not enough to keep you off steep slopes, there is also the possibility of avalanches breaking near the ground. Slopes that stayed shallow through the early season have weak snow at the ground that just got a big load put on top (<strong><a href="https://www.youtube.com/watch?v=pStZS8rCbJ0&amp;list=PLXu5151nmAvSbcbVf…;). Human triggered avalanches are likely and the avalanche danger is rated CONSIDERABLE.</p>

<p>If you get out, please send us your observations no matter how brief. You can fill out an&nbsp;<strong><a href="https://www.mtavalanche.com/node/add/snow_observation">observation form</a></strong>, email us (<strong><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></strong&gt;), leave a VM at 406-587-6984, or Instagram (#gnfacobs).</p>

<p>New snow and strong wind are the avalanche story today in the northern mountains. In the last 48 hours 10” fell in Hyalite, 13” in the Bridger Range and 16” around Big Sky. Snow water equivalent (<u><strong><a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2…;) totaled 1-1.5” with most of it falling yesterday and last night making it the biggest snow storm since October 20^th. Strong west wind is loading slopes with dense drifts. Avalanches will break naturally near the ridgelines in wind-drifted snow. If you venture into steep terrain, even on non-wind loaded slopes, you are likely to trigger an avalanche. Slides will occur in the new snow, and in areas like Buck Ridge the snowpack is weak at the ground and avalanches will break deep and wide. Traveling in or underneath avalanche terrain is not a good idea. For today, the avalanche danger is rated HIGH on all wind-loaded terrain and CONSIDERABLE on all other slopes.</p>

<p>The mountains south of Big Sky to West Yellowstone received 10-12” (1” SWE) in the past 48 hours. Strong west wind is drifting snow at the ridgelines which will be susceptible to avalanching. Yesterday, Dave and I went to Bacon Rind and found weak, sugary snow at the ground struggling to support the new snow (<strong><a href="https://youtu.be/Ww-vCQEg-wA">video</a></strong&gt;), so we descended our uphill track to be safe. The weight of a skier or rider can trigger an avalanche, even at the bottom or side of a slope. Be vigilant about avoiding steep terrain and flatter <a href="https://avalanche.org/avalanche-encyclopedia/runout-zone/">runout zones</a>. For today, the avalanche danger is rated CONSIDERABLE on all slopes.</p>

<p>In the last 48 hours the mountains around Cooke City have 12” of new snow measuring .9” SWE, and reportedly higher amounts at upper elevations. Winds have been blowing this new snow around and both natural and human triggered slides are on the menu. Small, natural avalanches were seen yesterday by multiple parties (<strong><a href="https://www.mtavalanche.com/node/21414">details</a></strong&gt;). Ian and his partner rode around assessing the conditions and concluded that he does not trust the stability. As he says in his <strong><a href="https://youtu.be/2JZIsEvkGYY">video</a>,</strong&gt; “It’s been snowing, blowing, we’ve got weak layers in the snowpack…play it safe, keep it mellow.” Additionally, some slopes have weak, sugary snow at the ground that could be triggered from thinner areas (<strong><a href="https://youtu.be/FAgWx6yXR2U">video</a></strong&gt;). Given the likelihood of triggering avalanches in the new snow as well as the potential for deep slides breaking at the ground, the avalanche danger is rated CONSIDERABLE today.</p>