20-21

<p>In the Bridger, Gallatin and Madison Ranges and Lionhead area, 4-6” fell in three hours measuring .5” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</u></a>-SWE. The snowpack was loaded quickly and more snow today will continue raising the avalanche potential. Ian toured into the Throne of the northern Bridger Range yesterday and found conditions to be dismal: thin and weak. In his <a href="https://youtu.be/js1BXvovZ4I"><strong><u>video</u></strong></a&gt; he describes a poor snow structure which will be especially untrustworthy with today’s new snow.&nbsp;</p>

<p>Since Friday there have been <a href="https://www.mtavalanche.com/avalanche-activity"><strong><u>14 reports of avalanche activity</u></strong></a><strong>,</strong> some noting multiple slides. These were breaking on weak layers buried in the snowpack: near the ground and also midpack. I investigated a major avalanche cycle in Lionhead on Monday (<a href="https://youtu.be/CI0HFvtLrf4"><strong><u>video</u></strong></a&gt;, <a href="https://www.mtavalanche.com/node/24045"><strong><u>details</u></strong>…;), the same day a sledder triggered an avalanche in the area. Also on Monday, Dave looked at a monster avalanche near Bacon Rind that was skier triggered from far away (<a href="https://youtu.be/dVWv0RA9WMM"><strong><u>video</u></strong></a&gt;, <a href="https://www.mtavalanche.com/node/23991"><strong><u>details</u></strong>…;).&nbsp; In&nbsp; Taylor Fork (<a href="https://www.mtavalanche.com/node/24014"><strong><u>video and details</u></strong></a>), <a href="https://www.mtavalanche.com/node/24051"><strong><u>Speciman Creek</u></strong></a> and <a href="https://www.mtavalanche.com/node/24056"><strong><u>Fawn Pass</u></strong></a> more avalanches and red flags (whumpfing and cracking) were seen.</p>

<p>Snowfall will continue and the wind is blowing strong enough to create drifts which add even more weight to an unstable snowpack.&nbsp; Stay clear of avalanche terrain. It will be easy to trigger slides during the storm. Traveling near or under avalanche terrain is a dangerous proposition and the danger is rated CONSIDERABLE on all slopes.</p>

<p>The mountains around Cooke City received 3” of snow with southwest wind gusting into the 30s. Weak layers of faceted crystals 1-2’ deep and another buried 3’ deep avalanched on many slopes after last week’s snowfall. A <a href="https://www.mtavalanche.com/node/24021"><strong><u>large avalanche on the Fin</u></strong></a> broke deeply on Saturday and over the weekend skiers noted <a href="https://www.mtavalanche.com/node/23997"><strong><u>many other avalanches</u></strong></a> on different aspects and elevations. If snowfall continues the danger will rise. With limited visibility, wind and snow, it is a good idea to avoid steep slopes. At the first sign of instability, such as cracking , collapsing or fresh avalanches, hightail it away from avalanche terrain. For today the avalanche danger is rated MODERATE, but could rise to CONSIDERABLE if 6+” fall during the day.&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>

<p>Lionhead and the Southern Gallatin and Southern Madison Ranges received two feet of snow last week (1.5-2.2” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/or/snow/?cid=nrcs142p2… water equivalent</a>-SWE) and subsequently experienced a significant avalanche cycle. Yesterday, riders near Targhee Peak triggered an avalanche from off to the side that failed near the ground (<strong><a href="https://mtavalanche.com/node/24049">details and photos</a></strong>). At Lionhead, Doug noted that there were “LOTS of avalanches” on all aspects and elevations and we are still worried about human-triggered slides (<strong><a href="https://www.youtube.com/watch?v=CI0HFvtLrf4&amp;list=PLXu5151nmAvQDzKmH…;, <a href="https://mtavalanche.com/photos">photos page</a></strong>). I toured to Ernie Miller Ridge to look a 1500’ wide, human-triggered avalanche that failed on sugary snow near the ground (<strong><a href="https://www.youtube.com/watch?v=dVWv0RA9WMM&amp;list=PLXu5151nmAvQDzKmH…;). We experienced some collapsing but the weak layers are adjusting and the sensitivity to triggering is decreasing.</p>

<p>Give this year’s weak snowpack more time to adjust before entering steep terrain and avoid slopes where increasing winds create fresh drifts. Utilize careful route-finding along with a conservative mindset today. Human-triggered avalanches are possible and the danger is MODERATE.</p>

<p>During and immediately following last week’s snow in Cooke City, many natural and human-triggered avalanches broke in at the interface between the old snow and the new snow on a thin layer of weak facets 1-2’ deep (<a href="https://www.mtavalanche.com/node/23997"><strong>details</strong></a&gt;, <a href="https://www.mtavalanche.com/images/21/skier-triggered-slide-west-cooke"…;, <a href="https://www.mtavalanche.com/images/21/remote-triggered-cornice"><strong…;). &nbsp;Other avalanches failed on a stripe of surface hoar or weak facets buried 3’ deep (<a href="https://mtavalanche.com/node/24021"><strong>details and photo</strong></a>, <a href="https://mtavalanche.com/images/21/cooke-city-natural-old-snow"><strong>…;). Doug provides an explanation of these layers in his <a href="https://youtu.be/Ui1wdUHE56E"><strong>video</strong></a&gt; from last week. Today, increasing winds will create fresh drifts of snow that will avalanche under the weight of a rider or skier. Recognize and avoid these areas by watching for plumes of blowing snow, feeling for harder or packed snow at the surface and noticing shooting cracks from your skis or sled.</p>

<p>Safe travel through and around avalanche terrain requires a thorough snowpack assessment and dialing back objectives if you notice any signs of instability such as recent avalanche activity, collapsing, or cracking. Human-triggered avalanches are possible and the danger is rated MODERATE.</p>

<p>Snow early last weekend in the Northern Gallatin, Northern Madison and Bridger Ranges primarily resulted in avalanches within the 7-11” of new snow such as slab avalanches observed in Beehive Basin and loose snow avalanches in Hyalite and the Bridger Range (<a href="https://www.mtavalanche.com/images/21/natural-avalanche-beehive"><stron…;, </u></strong><a href="https://www.youtube.com/watch?v=qq8_qX60izk&amp;feature=emb_title"><str…;, <a href="https://mtavalanche.com/node/23975"><strong>details and photos</strong></a>). Some avalanches, like those near Maid of the Mist in Hyalite and in Dudley Creek near Big Sky, broke deeper in the snowpack on buried weak layers (<a href="https://www.mtavalanche.com/images/21/natural-avalanche-maid-mist"><str…;, </u></strong><a href="https://www.mtavalanche.com/images/21/dudley-creek-slides"><strong>phot…;). Today, avoid fresh drifts of snow created by increasing winds and carefully look for signs of instability as a reason to dial back objectives for the day. Human-triggered avalanches most likely within the top foot of the snowpack and the avalanche danger is MODERATE.</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>