22-23

Snowpack at 8000 ft in pioneers is about 2 feet deep and mostly facets. About a foot of 3 mm large squares on the ground, a slightly more dense 4F- layer of crust and facets and another foot on top of that of soft NSF and new snow. Intentionally triggered a very small test slope, slab failed on the lower facet layer. See pics of quick pit and test slope results. Boot and ski penetration to the ground. Weak.

Dillon Area, 2022-12-27

Snowpack at 8000 ft in pioneers is about 2 feet deep and mostly facets. About a foot of 3 mm large squares on the ground, a slightly more dense 4F- layer of crust and facets and another foot on top of that of soft NSF and new snow. Intentionally triggered a very small test slope, slab failed on the lower facet layer. See pics of quick pit and test slope results. Boot and ski penetration to the ground. Weak.

Dillon Area, 2022-12-27

Heavy snow but non-reactive on Texas Meadows

Date
Activity
Skiing

Toured up to Texas Meadows yesterday, it was spring-like conditions the whole way. We dug a pit at approximately 7600ft on an east aspect, HS was 114cm, and we got an ECTx. There was 10 to 20cm of weak rounds on the ground, and a layer of weaker snow at about 67cm. Our shovel shear broke on the 67cm layer, but it wasn't planar.

Region
Bridger Range
Location (from list)
Texas Meadow
Observer Name
Brian Richards

GNFAC Avalanche Forecast for Tue Dec 27, 2022

Snowpack and Avalanche Discussion

<p>Dangerous avalanche conditions exist in the mountains around Cooke City and West Yellowstone. Cooke City has received 8” of wet snow in the last 48 hours, with 2” near West Yellowstone. Strong winds from the south to southwest are gusting to 55 mph and blowing snow into unstable drifts at many elevations and aspects that are likely to avalanche. A storm bringing 4-8” of snow during the day will increase the danger on all slopes. In addition, two weak layers buried one foot deep and near the ground make much larger avalanches possible.</p>

<p>Yesterday, a splitboarder riding just outside our advisory area near Cooke City intentionally triggered an avalanche breaking 6-18” deep and saw cracks shooting from the nose of his board (<a href="https://www.mtavalanche.com/node/27341"><strong><span>observation and photos</span></strong></a>). Similar to what Alex and Doug found at Lionhead this weekend (<a href="https://www.youtube.com/watch?v=F8HKebJ_OJA&amp;list=PLXu5151nmAvTi1DBS…;, <a href="https://www.mtavalanche.com/node/27323"><strong><span>observation</span…;), a boarder in Republic Creek confirmed seeing a reactive weak layer buried a foot deep (<a href="https://www.mtavalanche.com/node/27345"><strong><span>observation</span…;).</p>

<p><span>Careful route finding and snowpack evaluation are essential. Avoid all steep, wind-loaded slopes, and expect the danger to increase with today’s snow. The avalanche danger is CONSIDERABLE. </span></p>

<p>The avalanche story is complicated in the Madison, Gallatin and Bridger Ranges where problems including rain and wet snow at lower elevations, new snow during the day, strong winds creating unstable drifts and two weak layers buried a foot deep and near the bottom of the snowpack make avalanches possible.</p>

<p>Yesterday, a skier near Big Sky triggered “whumphing” on a slope indicating unstable weak layers (<a href="https://www.mtavalanche.com/node/27334"><strong><span>observation</span…;). I found a weak layer of near-surface facets buried a foot deep at Mount Blackmore and saw the wind drifting snow (<a href="https://youtu.be/jjrqrzYhpIc"><strong><span>video</span></strong></a&gt;). Another group at Blackmore got unstable results with their test propagating on the near-surface facet layer. Alex confirmed multiple weak layers at Buck Ridge and saw recent avalanches (<a href="https://www.youtube.com/watch?v=C2HXtmgNkt8"><strong><span>video</span>…;). And the Big Sky Ski Patrol noted “very sensitive” slabs of wind-drifted snow 4-6” deep during routine mitigation.</p>

<p>Today, precipitation will begin as rain at lower elevations. Yesterday, on our drive down Hyalite Canyon, we observed small wet snow avalanches on the roadcuts. Any rain will have a destabilizing effect on the snowpack.</p>

<p>Keep your head on a swivel looking for signs of instability because human-triggered avalanches are possible, and the danger is rated MODERATE.</p>

<p><span>Please share avalanche, snowpack or weather observations via our<a href="https://www.mtavalanche.com/node/add/snow_obs"><span&gt; </span></a><a href="https://www.mtavalanche.com/node/add/snow_obs"><strong><span>website</s…;, email (<strong>mtavalanche@gmail.com</strong>), phone (406-587-6984), or Instagram (#gnfacobs). <span><span>&nbsp;</span></span></span></p>

<p><span>Dangerous avalanche conditions exist in the mountains around Strong winds are gusting to 55 mph and blowing snow into unstable drifts at many elevations and aspects that are likely to avalanche. A storm bringing 4-8” of snow during the day will increase the danger on all slopes. Two weak layers buried one foot deep and near the ground make much larger avalanches possible. Today, careful route finding and snowpack evaluation are essential. </span></p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

Thursday, December 29, 6:30 p.m., Avalanche Presentation and Raffle (great odds of winning!) at MAP Brewing in Bozeman. Free.

Two avalanches on Buck Ridge

Buck Ridge
Northern Madison
Code
HS-N-R3-D2-O
Elevation
9400
Aspect
N
Latitude
45.17190
Longitude
-111.38000
Notes

We saw two large avalanches in the 2nd Yellow Mule that were probably 2-3 days old, and likely broke on the weak layer near the bottom of the snowpack. Hard slabs on heavily wind-loaded slopes. 

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
30.0 inches
Vertical Fall
200ft
Slab Width
200.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year