24-25

Stable, variable snowpack in N. Bridgers

Date
Activity
Skiing

We found soft snow on north-facing terrain in Sac Bowl and off Pomp Peak, skiing until about 2 p.m. on 4/14. The recent storm winds stripped some southeast facing terrain down to crust, but had deposited 4-6 inches of creamy pow in sheltered N zones. Skiing was mostly bomber, with the exception of some wind slab we avoided on a start zone immediately below ridgeline in Sac Bowl. Saw a few small dry loose / point release slides in southern Bridgers, but nothing in N. Bridgers except for old debris piles. 

Region
Bridger Range
Location (from list)
Sacajewea Peak
Observer Name
B. Rad

GNFAC Avalanche Forecast for Mon Apr 14, 2025

Snowpack and Avalanche Discussion

<p>Today, the 10” of recent snow in Cooke City will get hit by above-freezing temperatures and the powerful April sun for the first time. Natural and human-triggered <strong>wet loose avalanches are likely </strong>on steep slopes facing the southern half of the compass rose.<strong> </strong>These will start narrowly at a point and spread as they entrain this weekend’s snow. Rocks and cliff bands are common areas for these slides to start, and the underlying crusts make for slick sliding surfaces. These avalanches are most dangerous in steep and confined terrain where they don’t have room to spread out. Move to shadier and cooler north-facing aspects before the day’s warmth melts the surface snow. Cinnamon roll-like roller balls and small wet snow avalanches indicate that slopes are destabilizing rapidly.</p>

<p>Yesterday, ski guides in Cooke City noted numerous natural <strong>wind slab avalanches</strong> running long distances (<a href="https://www.mtavalanche.com/node/34907"><strong><span>observation</span…;). Strong winds during the weekend’s storm drifted snow into slabs two feet thick. Wind-loaded slopes are stabilizing, but some will still release under the weight of a skier or rider. Find better snow quality and safer conditions by looking for more sheltered terrain and avoiding the most heavily wind-loaded slopes below cornices.</p>

<p>Assess the stability of recent snow before considering skiing and riding steep terrain by watching for a moistening of the snow surface, obvious signs of instability and performing a quick extended column test down to the crust buried one to two feet deep.<span>&nbsp; </span></p>

<p><span>The danger in Cooke City is MODERATE for dry snow avalanches and will rise to CONSIDERABLE for wet snow slides.<span>&nbsp; </span></span></p>

<p>Cold temperatures refroze the snowpack and will delay the onset of wet snow instability in the Bridger, Gallatin, Madison, Lionhead and Centennial Ranges. As the day warms and the sun hits this weekend’s snow, there will be a few small <strong>wet loose avalanches</strong>, especially on rocky, south-facing slopes. With only a few inches of recent snow, these avalanches will only be a problem in very steep or extreme terrain where they could sweep a skier or rider off their feet, into obstacles and terrain traps. Redirect to cooler, northerly aspects if you observe pinwheels and small wet slides. Wet loose avalanches will be more significant in isolated areas in the upper reaches of the Northern Gallatin Range (<a href="https://www.mtavalanche.com/weather/stations/shower-falls-snotel-site">… Falls SNOTEL</span></strong></a>), where more snow fell in the last few days.</p>

<p>Outside of very steep and extreme slopes with southern aspects, the snowpack is generally stable, and avalanches are unlikely. The avalanche danger is LOW.</p>

Wind Slab Activity in Cooke City

COOKE CITY
Cooke City
Code
SS-N-R2-D2-I
Aspect Range
SE-NE
Latitude
45.02020
Longitude
-109.93800
Notes

I rode the motorized zone and noticed natural wind slab avalanches running pretty far on: East Henderson, SE Scotch Bonnet, East Miller, NE Crown Butte. D1.5-2.0

Loose wet debris from yesterday were also present in many places. 

Number of slides
4
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
Wind Slab
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Wind Slab and Wet Loose Activity in Cooke City

Date
Activity
Snowmobiling

I rode the motorized zone and noticed natural wind slab avalanches running pretty far on: East Henderson, SE Scotch Bonnet, East Miller, NE Crown Butte. D1.5-2.0

Loose wet debris from yesterday were also present in many places. 

Region
Cooke City
Location (from list)
COOKE CITY
Observer Name
Jake Mundt

GNFAC Avalanche Forecast for Sun Apr 13, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Wild weather yesterday likely threw down some </span></span></span></span></span></span><a href="https://avalanche.org/avalanche-encyclopedia/#graupel-rimed-particles">…; and other variations in the 10” of dense, new snow along with a </span></span></span></span></span></span><a href="https://www.mtavalanche.com/sites/default/files/snow_obs/2025-04/screen… of strong winds</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>. There are two avalanche problems to consider:</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Storm slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> - I’m unsure how well the new snow is bonded to itself and the old snow surface, but it should be dense enough to be a cohesive slab. Assess the stability of the new snow before getting into steep terrain - get onto small steep test slopes, step and ride above your partners tracks, and perform </span></span></span></span></span></span><a href="https://avalanche.org/avalanche-encyclopedia/#extended-column-test-ect"… ECT’s</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><strong><span><span>Wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> - Strong winds during the storm yesterday drifted the new snow and formed wind slabs that could be two feet thick. Look for places with fresh wind loading and ski or ride around those locations where there’s a good chance you’ll trigger a slide.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today near Cooke City the avalanche danger is CONSIDERABLE in any wind-loaded terrain with drifting from yesterday’s winds. Slopes untouched by yesterday’s winds have a MODERATE danger.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Cold temperatures have helped refreeze the snowpack ending wet snow problems. With minimal new snow there are minimal dry snow avalanche problems, but still watch out for shallow wind slabs that could sweep you off your feet.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Today the avalanche danger is LOW. For the few hardy folks venturing into out of the way places, watch out for isolated locations that may have received much higher snowfall amounts. Those places will have the danger and avalanche problems more similar to the Cooke City area.</span></span></span></span></span></span></p>