Skied from the summit of both Palace Butte and Maid of the Mist. Based on seeing no signs of snow instability and good terrain selection we had a grand day in the mountains. There was approximately 25 cms of new, dense snow. The SW Montana faceted snow at the ground resides every where we skied and snow above this layer is obviously well bonded.
We Traveled to the Two Top area. Due to low visibility and new drifting snow Our snow pit location was in a lower tree covered elevation. We observed a surprisingly strong snowpack void of the obvious buried SH layers we found higher. With new snow available for transport and strong SW winds we observed wind loading on NNE aspects in the area.
Snow Stability
Stability Rating:
Good
Confidence in Rating:
Moderate
Stability Trend:
Worsening
Bottom Line
The Buried SH layers are still present especially in higher elevation open slope areas. With the arrival of new snow, accompanied by strong winds the potential to form a wind slab over a PWL (Buried SH) could have serious consequence to riders in this area.
Advanced Information
Weather Summary
Cloud Cover:
Obscured
Temperature:
15°
Wind:
Strong , SW
New/Recent Snowfall:
1 inch of new snow reported from the previous night.
Winter storm warning had been issued for the area. 18'' of new snow in higher elevations followed by strong winds. We observed new snow available for transport at all elevations
Avalanche Observations
Avalanche Observation Comments:
None observed
Snowpack Observations
NNE aspect 7680' HS 175cm CTN
Avalanche Problems
Heightened awareness of increasing avalanche danger with the arrival of this storm.
Terrain Use
Our travel mindset for the day, to not travel in avalanche terrain over 30°.Due to low visibility, blowing and drifting snow our travel plan was impacted and our route was shortened. I learned later of 2 riders in the Keg springs area that dropped into Carrot canyon unable to get out due to a damaged Snowmobile they where rescued by Clark county SAR 03:30 this morning. All where cold tired but SAFE! A big thanks to Clark County SAR A reminder of the dangers of back country travel
<p><span><span><span><span><span><span>Heavy snowfall onto well developed weak layers has created very dangerous avalanche conditions. Both natural and human triggered avalanches are LIKELY today. Continued heavy snowfall today will keep pushing the snowpack further past its breaking point. There were already clear signs of instability before this heavy snowfall and conditions have deteriorated dramatically overnight (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=55VuPiasHgw"><span><span><span><strong>… yesterday on Buck Ridge</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). We’ve been telling you for the last month that conditions are going to get dangerous quickly when the weak layers get loaded - today is the day we’ve been warning you about. Avalanches can be triggered from below or break naturally above you as you’re crossing a runout zone. Avoid travel on or below slopes steeper than 30 degrees. The avalanche danger is HIGH.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Near West Yellowstone there is not quite enough new snow for an avalanche warning, but conditions are still quite dangerous. Large human triggered slides are likely. There are some extremely weak layers of surface hoar in the top couple feet of the snowpack. These layers avalanched earlier in the week during a wind event without any new snow (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27817"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). New snow and wind have now pushed the weak layers right to their breaking point, your added weight will be all it takes to trigger a dangerous slide. Stay off and out from under steep slopes. The avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Wind loaded slopes around Cooke City are the most worrisome today. Weak layers aren’t as widespread or touchy as they are elsewhere, but there is weak snow and where it has a slab of wind drifted snow on top avalanches will be easily triggered today. These slides will break deeper and wider than if it were just a wind drift without a weak layer. Avoid steep wind loaded slopes and carefully assess the weak layers in the upper snowpack before riding any steep slope. If heavy snowfall develops today, all slopes will quickly become more dangerous. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is CONSIDERABLE on wind loaded slopes, MODERATE on all others. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs). </span></span></span></span></span></span><span><span><span><span><span><span> </span></span></span></span></span></span></p>
<p> </p>
<p>In Island Park, large human triggered slides are likely. There are some extremely weak layers of surface hoar in the top couple feet of the snowpack. New snow and wind have now pushed the weak layers right to their breaking point, your added weight will be all it takes to trigger a dangerous slide. Stay off and out from under steep slopes.</p>
Do you like to hike? Do you like to ski? Then the King & Queen of the Ridge is for you. Hike, ski and raise money for the Friends of the Avalanche Center in their 2nd biggest fundraiser of the year. Join the effort to promote and support avalanche safety and awareness! Fundraising prizes for the top 5 individuals who raise over $500.
We toured into Beehive Basin for field day 3 of our Pro Avalanche 1 course. We chose to avoid all avalanche terrain today on our ascent and paralleled the private boundary to reach the ridge on the East of Beehive Basin. Each member of our group then completed a full pit profile just below the ridge on W aspects. My pit was dug on a W aspect at 9,012 ft on a 20-degree slope. No active wind loading was observed at the location of my pit. I found snow instabilities approximately 30 cm below the snow surface on a layer of very large-grained surface hoar (CT8 Q2, ECTP2, PST 75/100 End). There were two additional layers of surface hoar buried deeper in the snowpack, although these layers were not reactive and showed signs of rounding and sintering. The basal facets in our pit are rounding and gaining strength and we did not find any instabilities deeper in the snowpack. We would expect to see natural avalanche activity on wind-loaded slopes that have this layer of buried surface hoar if we were to tour into this zone again tomorrow.
Toured up between Flathead Pass and Ainger Lake/Bollywood Headwall. Three pits at different elevations and aspects summarized below.
Pit 1:
7600', E aspect, HS 100cm, ECTX, uploading full pit profile on SnowPilot. Poor structure but as of now a stable pit result. Could change quick with additional load.
Pit 2:
8100', NE aspect, HS 160cm, ECTP28@120cm (in hindsight performed test on deeper side of column, still got an unstable result)
Pit 3:
8100', SE aspect, HS 90cm, ECTP22@30cm
Overall obs; soft snow in sheltered areas, particularly on E-->SE aspects above 7600' (and quite good skiing!); wind blasted crust on exposed N aspects and on ridge lines; below 7600' was very much survival skiing w/ bottomless facets and breakable crust (not such great skiing...); wind slabs on leeward slopes ~15-20cm thick, subtly stiffening through the day and shooting cracks ~5' from skis where wind slab present; strong winds out of generally the NW; cloud ceiling ~8400', ridge line was just barely obscured.
Low angle pow skipping was excellent from ~8100' to 7600'.
We rode in through 1st, 2nd, and 3rd Yellowmule. There was 5-8” inches of recent snowfall. The only signs of instability we observed was some minor cracking in a drift at the entrance to Second Yellowmule. However, the problem is lurking just under the surface of the snow. Depending on the location, we found one to three layers of surface hoar in the upper 20” of the snowpack. At the top of Second Yellowmule we found repeatable ECTP1s and 2s on a layer of surface hoar 6” below the surface and repeatable ECTP 11s and 12s on a surface hoar layer 18” deep.
The depth and number of weak layers is somewhat irrelevant. The upper snowpack is on edge. Currently, human-triggered avalanches are likely on wind-loaded slopes. We choose to stay clear of avalanche terrain today. And, if tonight’s storm produces as forecast, we will be looking at an avalanche warning by tomorrow morning with natural and human-triggered avalanches likely to very likely. These could fail across wide sections of slopes and be triggered from a distance. We are preparing to stay off steep slope and clear of the runout zones.
