24-25 | Gallatin National Forest Avalanche Center

Extreme Winds in Dutchman Basin

Date

Wed, 02/05/2025 - 12:40

Activity

Snowmobiling

Figured I would send in some observations as we were out yesterday in Whits Lake back in Dutchman's Basin and with extreme wind the snow was getting moved around and the wind was putting snow in unusual locations. This was a wind loaded hill but a very shallow angle hill maybe 20-25 degrees. Snow broke on an old layer before this past weekend's storm, that slab was probably 14-24" think in spots. Snow was generally stable other than wind blown spots.

Region

Southern Madison

Location (from list)

Other place

Observer Name

J Kurtz

The Wind is the Key Player at Mount Blackmore - 6 February 2025

Read more about The Wind is the Key Player at Mount Blackmore - 6 February 2025

Breaking and Small Slide on Bridger D route

Date

Wed, 02/05/2025 - 12:45

Activity

Snowboarding

I was boarding Job 1 (E, NE aspect) in the Bridger D route. We had 6-8 inches of new snow and I triggered a large break, and 2-3 turns later triggered a small avalanche that traveled 30 ft rfar and was about 4 inches deep. I was the last one on the route before ski patrol closed it down.

Region

Bridger Range

Location (from list)

Bridger Bowl Weather Station - The Ridge

Observer Name

Griffin

Read more about Blackmore Lower Pitch Profile - 6 February 2025

Northern Gallatin, 2025-02-06

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Weird Conditions in the Madisons

Date

Wed, 02/05/2025 - 10:00

Activity

Skiing

Started touring from the road around 8:30, with temps just above 0F. Half an hour later and 200 feet higher (~6150 feet) we were down to base layers and temps were above freezing. The top 5cm of surface snow was moist for most of our tour, with about 15-20 cm of dry snow below, overlying a buried crust in most areas.

As we got higher (~7000 ft) we noticed roller balls from the previous day, as well as dust on the snow surface.

Above 8000 feet surface snow became mostly dry on northerly aspects but a surface MFcr or a thin layer of moist surface snow still existed on southerly aspects. We skied a northly aspect first and it wasn't too bad.

Around noon graupel showers turned into S2 snowfall with sustained strong winds at ridgetop. A very abrupt change in weather and snow conditions. As we descended and drove back to Bozeman the temperature inversion was still going strong.

Our main thoughts are that this bodes for weird things to come. The snow yesterday was falling on a crust at higher elevations, but burying cold (potentially faceted?) snow at lower elevations. There were signs of developing wet snow problems at higher elevations but mid-winter conditions at lower elevations. It seems like our standard way of thinking about avalanche problems/hazard distribution may have to become inverted along with the temperatures.

Region

Northern Madison

Location (from list)

Deer Creek

Observer Name

N deLeeuw

Weather and Avalanche Log for Thu Feb 6, 2025

Read more about Weather and Avalanche Log for Thu Feb 6, 2025

Mountain temps 25 degrees colder than yesterday

Read more about Bone Crusher avalanche

Swift Current lift shut down all day Wednesday 2/5/25 by ski patrol

Forecast link: GNFAC Avalanche Forecast for Thu Feb 6, 2025 GNFAC Avalanche Forecast for Fri Feb 7, 2025

Northern Madison, 2025-02-06

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GNFAC Avalanche Forecast for Thu Feb 6, 2025

Snowpack and Avalanche Discussion

My head is still spinning trying to make sense of avalanche conditions following this roller coaster of weather, and frankly I don’t have any trust in the snowpack at the moment.

The biggest issue is recent hurricane force winds from the south. The Big Sky Ski Patrol intentionally triggered an avalanche with explosives on a slope loaded by these winds producing a slide up to 7 feet deep breaking on the old snow surface from dry weather in late January. They haven’t seen an avalanche like that on that slope in 40-50 years. What do you think we might find in the backcountry? (<a href="https://www.mtavalanche.com/node/34027"><…;, <a href="https://www.kbzk.com/news/local-news/avalanche-triggered-during-mitigat… story</a>).

Near Cooke City, large avalanches have been spotted on <a href="https://www.mtavalanche.com/images/25/avalanche-north-crown-butte"><spa… Butte</a>, <a href="https://www.mtavalanche.com/images/25/scotch-bonnet-north-avalanche"><s… Bonnet</a>, <a href="https://www.mtavalanche.com/images/25/natural-avalanche-mt-henderson-ne…;, and<a href="https://www.mtavalanche.com/images/25/natural-avalanche-miller-ridge-ne…; Miller Ridge</a>. Near West Yellowstone on Lionhead, slightly smaller but many fresh wind slabs were <a href="https://www.mtavalanche.com/node/33978"><… on Tuesday</a>. Yesterday at low elevations in the cold air (below the inversion) on Mt Ellis in the northern Gallatin Range, a skier triggered and spotted <a href="https://www.mtavalanche.com/node/34015"><… storm slab avalanches in the new snow</a>.

When you add it all up, these are dangerous avalanche conditions creating several avalanche problems stacked on top of each other - wind slabs, persistent slabs, storm slabs.

<ol>
<li>There are weak layers of small facets buried 1-3 feet deep that formed during dry weather in late January. These weak layers seem more widespread the further south you go. See this video near <a href="https://youtube.com/shorts/y7Nm5dbbBqQ?feature=shared"><spa… Yellowstone</a> and this one near <a href="https://youtube.com/shorts/BzI5yK0R7FU?feature=shared"><spa… Sky</a>.</li>
<li>There has been a lot of snow from this weekend and yesterday.</li>
<li>The snow surface got a coating of dust and then became wet on some slopes during warm temperatures late Tuesday.</li>
<li>There have been really strong winds from the south and west. Shifting wind directions and new snow yesterday will make it harder to identify recent wind slabs.</li>
</ol>

For today the avalanche danger is CONSIDERABLE. I’m unsure of the likelihood of triggering avalanches today, but I know these are dangerous conditions requiring careful snowpack evaluation, cautious route finding, and conservative decision making.

The main avalanche problems in the Bridgers are tied to yesterday’s 6-9” of new snow and winds from the north, south, and west both yesterday and earlier this week creating a wind slab avalanche problem. Storm slabs that were sensitive yesterday during high snowfall rates shouldn’t be much of an issue today but still something to watch out for.

<ul>
<li>Skiers north of Bridger Bowl on the ridge spotted numerous wind slabs that released naturally like <a href="https://www.mtavalanche.com/images/25/wind-slab-crown-hourglass-couloir… in the Hourglass couloir</a> not too deep but 200’ wide. </li>
<li>Another group below heard those avalanches rumbling down but were in safe locations.</li>
<li>On Tuesday, three skiers triggered an avalanche on a wind-loaded terrain feature on Saddle Peak that ran 400 vertical feet. Thankfully, no one was caught, and the slide stopped above the large cliffs (<a href="https://www.mtavalanche.com/node/34007"><span…;).</li>
<li><a href="https://www.mtavalanche.com/node/34014"><… north towards Ross Peak</a>, skiers observed cracking and many small storm slab avalanches that seemed to be at lower elevations underneath the inversion  where the new snow landed on old cold snow. </li>
</ul>

Today dangerous avalanche conditions exist where winds deposited yesterday’s snow and the danger is CONSIDERABLE on wind loaded slopes. Non-wind loaded slopes have a MODERATE danger where there may be some lingering storm slab instabilities.