22-23

Skier triggered wind slab

Date
Activity
Skiing

From instagram: Skier triggered windslab on Scotch bonnet near Cooke City. Approximately 75 ft wide.

Region
Cooke City
Location (from list)
Rasta Chutes

Natural Avalanche in Bridgers

Saddle Peak
Bridger Range
Code
SS-NC-R2-D2-I
Elevation
8500
Aspect
E
Latitude
45.79430
Longitude
-110.93600
Notes

South of Saddle Peak, ~8500', ENE aspect, 2-3' crown depth estimated and likely cornice-triggered. N-facing snow remained dry until the latter afternoon when a high sun angle cooked everything but the truest due north. Avalanche appeared to be all new snow likely on a PWL buried near the end of March. Winds moving snow up high, but everything appeared locked on.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Cornice fall
R size
2
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
24.0 inches
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From obs: "South of Saddle Peak, ~8500', ENE aspect, 2-3' crown depth estimated and likely cornice-triggered. N-facing snow remained dry until the latter afternoon when a high sun angle cooked everything but the truest due north. Avalanche appeared to be all new snow likely on a PWL buried near the end of March. Winds moving snow up high, but everything appeared locked on."

Bridger Range, 2023-04-06

Conditions Changing Quickly

Date
Activity
Snowmobiling

We rode through Carrot and Sage Basin and up to the weather station above Sunlight Basin. We dug a pit on a SE facing aspect to see if the snowpack was transitioning from dry to wet. At 9,200' the air temperature was 18 F and the snowpack was dry throughout. Despite the cool temperature the snow surface was close to becoming wet (31 F). This was a good reminder that the sun angle has a significant impact on the snow surface this time of the year, which causes rapidly changing conditions. Additionally, we had an ECTP 13 on a layer of near surface facets 1.5' below the surface sitting on top of a melt freeze crust. This weak layer and the one near the bottom of the snowpack remain a concern.

Region
Southern Madison
Location (from list)
Taylor Fork
Observer Name
Ian Hoyer, Alex Haddad

Natural Avalanche in Bridgers

Date

South of Saddle Peak, ~8500', ENE aspect, 2-3' crown depth estimated and likely cornice-triggered. N-facing snow remained dry until the latter afternoon when a high sun angle cooked everything but the truest due north. Avalanche appeared to be all new snow likely on a PWL buried near the end of March. Winds moving snow up high, but everything appeared locked on.

Region
Bridger Range
Observer Name
G. Antonioli

GNFAC Avalanche Forecast for Thu Apr 6, 2023

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Yesterday, skiers north of Bridger Bowl triggered a small slide near Texas Meadow (</span></span></span></span></span></span><a href="http://www.mtavalanche.com/node/28972"><span><span><span><strong><span>… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). It involved newer snow and was triggered from 35 feet away which indicates a connected weak layer. It did not look deep. On Sunday, skiers got a </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28941"><span><span><span><strong><span… collapse (whumpf) in Beehive Basin</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, another indicator of a buried weak layer. Our last round of significant avalanche activity was Sunday, and many of these involved wind-loaded slopes. Given all this action, it's a good idea to test the upper 2-3 feet of the snowpack.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Large avalanches breaking 5-6 feet deep are not common, but are still on our mind. A few released on Sunday in </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28949"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28924%5C"><span><span><span><strong><s… City</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> and the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28900"><span><span><span><strong><span… Range</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>. We can’t tell which slopes may break deep, which causes me heartburn. I do not like roll-the-dice scenarios, even when the odds of losing are low. Sticking to shallow-angled terrain offers complete safety but can be less fun, and choosing terrain with clean fall lines (no cliffs, trees or gullies) is much better than not, but isn’t fool proof.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The sun is high in the sky and strong. Wet, loose snow slides will occur on steep slopes and off of cliffs. If the snow surface gets sun it will likely get wet. I only expect wet point release avalanches on east and south facing slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Given yesterday’s remotely triggered slide, deeper layers that are still worrisome, and the potential for wet slides, the avalanche danger is rated MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Our last daily forecast will be this Sunday, April 9. We will issue weather and avalanche observations every Monday and Friday through April. Please share avalanche, snowpack or weather observations via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>

<p>Yesterday, a skier remotely triggered a shallow slide north of Bridger Bowl and on Sunday there were avalanches throughout southwest Montana breaking on a buried weak layer, some quite deep. These deep avalanches are difficult to trigger, but the shallow ones will not be. Investigate the upper 2-3 feet of the snowpack for instability and be mindful of the possibility of triggering something deeper. Sunny skies and above freezing temperatures will create wet, loose slides on slopes getting the sun.</p>

Upcoming Avalanche Education and Events

Events and Education Calendar.

Skinner triggered slide north of the hourglass. Run name unknown. Remotely triggered from ridge line; snowboarder said he was skinning 35 feet away from trigger point; no one buried. I also observed point releases as I was skinning up to texas meadows; snow seemed to change quickly under blue skies and increasing temperature. Slide ran in front of me, taking out the skin track. 

Bridger Range, 2023-04-06