21-22
Emigrant PWL
Date
Activity
Skiing
Hey guys,
Tricky conditions out there currently. After a mild winter with relatively low hazard, this last week has upped the ante. Super sad to hear about all these near misses and fatalities recently but they definitely highlight the fickleness of our current spx. We definitely have a PWL resting above and below a MF crust w/in the top meter of the spx. At 10k yesterday on a SE facing 40degree slope we observed all of the structural lemons and got unstable results in our tests. CT12 Q2, ECTP11 on 1mm facets above a MF crust. The crust is 10cm thick and P/K hard w 4F slab on top. On a NE face (9,500', 35 degree) later in the afternoon we were able to get propagation below the crust down closer to 1 meter (CT12 again and ECTP26). A skier in a NE feature pulled out a small pocket (D1) that stepped down below the crust highlighting the current sensitivity. Needless to say we did not summit nor did we feel comfortable in larger features where you could potentially get widespread prop. What a strange spring!
cheers and be safe
-A
Region
Out of Advisory Area
Location (from list)
Emigrant Peak
Observer Name
A. Newman
Weak snow collapsing on NE aspects in beehive
Date
Activity
Skiing
We were one basin north of Bear basin on the NE ramp of Bear Peak (10400'). We were on a NNE aspect of the ramp taking off our skis to dig a pit when we noticed how rotten the snow was, boot pen was immediately up to our waste. My partner noticed a subtle collapse and a couple seconds later we both felt and audibly heard a larger collapse. There were a few shooting cracks about 5-8 feet up the slope from us and arcing about 10 feet across the slope. We gingerly put our skis back on and traversed down and away from to a low angle bench.
Digging hasty hand pits and probing with our poles we continued to notice hard crusts and slabs with weak snow beneath them on E and NE aspects protected from the sun but less so on anything slightly south facing or west. During a quick column test on a SE aspect at about 10200' the result was CT14.
Region
Northern Madison
Observer Name
Bryce Gordon
GNFAC Avalanche Forecast for Sun Mar 20, 2022
Snowpack and Avalanche Discussion
<p>Heavy snowfall this morning followed by moderate northwest wind will make human triggered avalanches likely on wind-loaded slopes and possible on non-wind loaded slopes today. A person can trigger large, dangerous avalanches that break 1-3 feet deep on buried weak layers, or fresh drifts of snow up to a foot deep.</p>
<p>Over the last week avalanches were triggered by skiers near Cooke City (<a href="https://www.mtavalanche.com/images/22/skier-triggered-slide-mount-abund…;), Big Sky and in Hyalite (<a href="https://youtu.be/f6wLR3tLNa8"><strong>Wyoming Bowl video</strong></a>, <a href="https://www.mtavalanche.com/node/26199"><strong>Mt. Blackmore slide details</strong></a>), by snowmobilers near Buck Ridge (<strong><a href="https://www.mtavalanche.com/images/22/rider-triggered-avalanche-near-mu…;) and broke naturally throughout the forecast area (<strong><a href="https://www.mtavalanche.com/avalanche-activity">activity log</a></strong>). Yesterday Ian and I rode around Lionhead near West Yellowstone and noted very weak snow buried about a foot deep that was not yet unstable, but today’s snow could create a widespread instability (<strong><a href="https://www.youtube.com/watch?v=xc770oqXMsE&list=PLXu5151nmAvT1nrM2…;). We have already seen these weak layers become unstable with snow earlier in the week and cause avalanches near Cooke City, the Bridgers, Hyalite and Big Sky, and today’s snow will cause more.</p>
<p>Avoid slopes with fresh drifts of snow. If you plan to ride or travel in steep terrain, first carefully assess the snowpack on safe, low-angle slopes similar to those you plan to ride. Dig down a couple feet to look for and test buried weak layers. Stay off steep slopes if you see natural avalanches or experience cracking and collapsing of the snowpack under your feet, skis or snowmobile. Avalanches breaking on persistent weak layers can be triggered from flatter terrain near or below steep slopes, so pay attention to what is above you and be cautious crossing underneath steep slopes.</p>
<p>Today, avalanche danger is rated CONSIDERABLE on wind-loaded slopes and MODERATE on non-wind loaded slopes.</p>
<p>If you get out, please send us your observations no matter how brief. You can submit them via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</p>
From email 3/20/22: "Visible from ridge dividing Republic and Wyo Creeks. N facing. Cornice drop with a step down 1/2way down?" Photo: N. Stayner
Two natural cornice fall triggered slides at Lionhead
Lionhead Ridge
Lionhead Range
Code
SS-NC-R2-D2-O
Elevation
9000
Aspect Range
NE-N
Latitude
44.71450
Longitude
-111.31800
Notes
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Cornice fall
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
12.0 inches
Vertical Fall
700ft
Slab Width
50.00ft
Images
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
We saw this natural avalanche on 3/19/22 appeared to be within 24 hours old and triggered by cornice fall that broke out a slab below. Northeast aspect at 8,800' on Lionhead Ridge. Photo: GNFAC
Avalanche Details: Two natural cornice fall triggered slides at Lionhead
Forecast link: GNFAC Avalanche Forecast for Mon Mar 21, 2022
Lionhead Range, 2022-03-19
Forecast link: GNFAC Avalanche Forecast for Mon Mar 21, 2022