120 cm pit depth
9100 ft
South Aspect
ECTNR
45.03938, -109.97534
Found ~14 inches of new snow that seemed to be bonding well to a 4F layer beneath it. Found facets and a crust near the ground but they didn't seem to be reactive.
120 cm
ECTP22
Failed on facets at the ground
9750 ft
44.98452, -109.92523
West aspect
ECTNR
140 cm pit depth
West Aspect
9900 ft
<p>Since Wednesday the mountains near Cooke City got 2 feet of snow equal to 2.4” of <a href="https://www.nrcs.usda.gov/wps/portal/nrcs/detail/null/?cid=nrcseprd1314… water equivalent</a> (SWE), and over the last week received at least 4 feet of snow equal to 3.8” SWE. While this new snow is welcome, it creates dangerous avalanches conditions today. Avalanches breaking in the new snow are likely, especially where snow is drifted into stiffer slabs. The snow that fell over the last week makes up 30% of the total snowpack (measured in SWE) near Cooke City. This is a relatively heavy weight for the snowpack and any weak layers need time to adjust. The additional weight of a person could tip the scales and trigger an avalanche deeper in the snowpack which would surely be large and potentially deadly. Today it is best to stay off and out from underneath slopes steeper than 30 degrees. Human triggered avalanches are likely and the avalanche danger is rated CONSIDERABLE.</p>
<p>Near West Yellowstone and in the Southern Madison and Gallatin ranges 14-20” (1.3 to 1.9” SWE) of snow fell since Wednesday. Today avalanches involving this new snow are possible to trigger. Increased wind speeds will form stiffer slabs of wind-drifted snow which a person could trigger. Ian and I rode in Taylor Fork yesterday and saw minimal signs of instability in the new snow (<strong><a href="https://youtu.be/rdVk9B7UbtQ">video</a></strong>), but that could change with more wind today. Avalanches could also break on weak layers near the ground (<a href="https://youtu.be/7EEn6f8-4fA"><strong>video</strong></a>). Yesterday skiers near Bacon Rind reported collapsing and “whumphing” of the snowpack and stability tests breaking on buried weak layers (<strong><a href="https://www.mtavalanche.com/node/25253">details</a></strong>). Before riding steep slopes carefully assess the potential for unstable buried weak layers. If you suspect buried weak layers or see signs that new snow or fresh drifts are unstable, avoid steep slopes. Today avalanches are possible and the avalanche danger is MODERATE.</p>
<p>Yesterday morning the Bridger Range got 3-10” of snow (0.3-0.7” SWE) while Hyalite and Big Sky got 3-4” of snow (0.2-0.4” SWE). Today avalanches are possible to trigger where this new snow is drifted into stiffer, thicker slabs. Watch for signs that drifts of new snow are unstable, such as fresh avalanches or cracks in the snow from your skis. If you see these signs, stay off of steep freshly wind-loaded slopes. Right now avalanches breaking deeper in the snowpack are not likely (<a href="https://www.youtube.com/watch?v=_MhpDHnH8So"><strong>Saddle Peak video</strong></a>, <a href="https://youtu.be/cf-qqv2Ssjw"><strong>Buck Ridge video</strong></a>, <a href="https://youtu.be/ePMCJs3qAs0"><strong>Beehive video</strong></a>), but on Thursday Big Sky Ski Patrol used explosives to trigger a 5 ft deep avalanche that broke on weak snow near the ground. This is our reminder to not forget about the potential weak layers deeper in the snowpack. Today, the avalanche danger is rated MODERATE on wind-loaded slopes and LOW on all others.</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>
Get your avalanche brain ready for the season at one of the many classes listed on our education calendar, and list of upcoming events below.
Every Saturday near Cooke City, 10 a.m.-3 p.m. FREE snowpack update and transceiver/rescue training. Stop by for 20 minutes or more at the Round Lake Warming Hut.
From email: "My partner and I went out to Ernie Miller today via the standard bacon rind uptrack. On the traverse across the moderate terrain, we experienced many whumpfs, some large enough to knock snow out of trees. We went up to about 9100ft on ole Ernest and dug a pit, performed an ect, and got propagation all the way across a layer maybe 4-6 inches above the ground at 25 whacks. On the same whack (the 25th), a layer about 12 inches above ground also collapsed and propagated across."
GNFAC,
I skied up in Beehive today, we skied partway down into Bear Basin behind the prayer flags. There was a few inches for new snow and the skiing was good. We dug a snowpit before the steep section partway into Bear Basin. We found poor structure but no instability. We tried to ski farther down but once we got down another 100 vertical feet there wasn't enough snow to ski so we turned around. We found an old wind slab at mid elevation on our skin back up the steep section which gave us pause, these old stiff windslabs were present at the ridgeline as well. I have attached a copy of the snowpit below.
Thanks for everything you guys do!
Spencer
