24-25
GNFAC Avalanche Forecast for Sat Jan 25, 2025
<p><span><span><span><span><span><span>Yesterday’s storm overperformed expectations in the mountains around Bozeman and Big Sky, with up to 8” of new snow piling up pretty quickly. Thin slabs were reported breaking easily in the new snow in the Bridgers and Hyalite (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33834"><span><span><span><strong><span…;). </span></span></span></span></span></span><span><span><span><strong><span><span>Wind Slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> are the primary concern today. Avalanches will be the most easily triggered and deepest on wind-loaded slopes. But don’t entirely discount slopes without much wind effect. Yesterday, Alex found surface hoar buried under the new snow on Buck Ridge (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33832"><span><span><span><span><span><…;). Weak layers have also been found under the new snow in Divide Basin (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33810"><span><span><span><span><span><…;) and Beehive Basin (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33824"><span><span><span><span><span><…;), so we suspect they’re fairly widespread. Remarkably thin, soft slabs can avalanche when they’re breaking on these persistent weak layers. Pay close attention to how deep the new snow is and think about the consequences of that new snow avalanching before getting on a steep slope. Watch for shooting cracks and recent avalanches as the clearest signs that the new snow is unstable.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Avalanches could also break under wind drifts that formed earlier in the week. If you’re happy with the stability of the most recent snow, dig down a couple feet to make sure these older wind slabs are bonded too. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>There has been less new snow (2-3”) around West Yellowstone, Island Park, and Cooke City, but human triggered avalanches are still a very real possibility today. There is a wide range to the likelihood and size of the potential slides today. There may be pockets where the newest snow has drifted deeply enough to avalanche. If you find a drift deeper than about 6”, expect it to be easily triggered. Deeper </span></span></span></span></span></span><span><span><span><strong><span><span>Wind Slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> could also break in older wind drifts that formed over the last week. Either steer clear of new and old wind drifts or watch for signs of instability and dig a snowpit to assess how well they’ve bonded before getting onto steep windloaded slopes.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Persistent Slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> breaking deep in the snowpack become less likely everyday without substantial snowfall and we haven’t seen slides on these weak layers recently, but we don’t quite trust them yet. The last big avalanches broke early last week near Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33528"><span><span><span><span><span><…; and </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33544"><span><span><span><span><span><…;) and one in the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/33584"><span><span><span><span><span><… Madison Range</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>. Keep the possibility of triggering one of these big slides in the back of your mind.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE.</span></span></span></span></span></span></p>
KING AND QUEEN OF THE RIDGE
Do you like to hike? Do you like to ski/ride? Then the King & Queen of the Ridge on 2/1 is for you. Hike, ride and raise money for the Friends of the Avalanche Center at Bridger Bowl this year! Join this fun event to promote and support avalanche safety and awareness! Fundraising prizes for the top 5 individuals who raise over $500.
Touchy Storm Slab Avalanches in Hyalite
Very touchy storm slabs formed throughout the day. 6-8” deep by 3pm. low density snow/slab but very fast moving.Photo: R Griffiths
Forecast link: GNFAC Avalanche Forecast for Sat Jan 25, 2025GNFAC Avalanche Forecast for Sun Jan 26, 2025
Very touchy storm slabs formed throughout the day. 6-8” deep by 3pm. low density snow/slab but very fast moving. Photo: R Griffiths
Forecast link: GNFAC Avalanche Forecast for Sat Jan 25, 2025
Touchy storm slabs in Hyalite
Very touchy storm slabs formed throughout the day. 6-8” deep by 3pm. low density snow/slab but very fast moving. We were able to trigger steep (35+) rolls with chunks of ice and even got one to go with a falling rope. We saw one natural (d1) that ran ~200’ down a gully near mummy 2.
Jan 24, Buck Ridge... We dug on an E facing slope at 9,400'. Snow depth was 155cm (5 feet) and we had an ECTN12 on the surface hoar layer 10" down. Photo GNFAC
Forecast link: GNFAC Avalanche Forecast for Sun Jan 26, 2025
Weak layer under new snow at Buck
We rode out Buck Ridge, through Second Yellow Mule, around the top of Third Yellow Mule, and through the top of McAtee. Snowed average S1 all day until 2pm when we rode out, and was still snowing up high at that time. Wind was light from the north. Minimal drifting and transport in the morning, but some very shallow, very soft slabs cracked on wind-loaded slopes near the ridge. Avalanche activity was limited to very small F- dry loose and some F- 2-4" soft slabs. Visibility was not great though. Natural and triggered by us on small test rolls.
There was 4" of new snow on average, and up to 8" of low density snow in places. Below today's snow there was 1-2" of snow from earlier in the week, and that was on top of a layer of surface hoar in some places or soft facets in most places.
The primary concern was and will be where the recent snow gets drifted into thicker or stiffer slabs. Recently buried weak layers might make these fresh wind slabs easy to trigger initially, and possible to trigger for longer into next week. Where today's new snow was not drifted there was minimal hazard aside from small dry loose avalanches.
We dug on an E facing slope at 9,400'. HS was 155cm and we had an ECTN12 on the surface hoar layer at 130cm above the ground.