21-22

GNFAC Avalanche Forecast for Sat Feb 26, 2022

Snowpack and Avalanche Discussion

<p>You can trigger a large avalanche today on weak layers buried around 2 feet deep. Yesterday, Alex visited the large avalanche on Mount Abundance that was triggered by a snowmobiler on Monday (<a href="https://www.youtube.com/watch?v=LHkbEAf1rlM&amp;list=PLXu5151nmAvT1nrM2…;, <a href="https://www.mtavalanche.com/node/25941"><strong><u>details</u></strong>…;). He dug nearby and got unstable results in his snowpack tests, showing that conditions are still ripe for triggering a similar slide. Each day without new snow makes it more difficult to trigger these slides, but it is still very much a possibility. Stack the odds in your favor by digging down to look for and test the weak layer before riding steep slopes, carrying avalanche rescue gear (beacon, shovel, and probe), and only exposing one person to avalanche terrain at a time. Large avalanches are possible and the avalanche danger is MODERATE.</p>

<p>While conditions are generally stable, there are a number of small and/or isolated avalanche hazards to watch for. Be on the lookout for thin fresh wind drifts or older drifts that haven’t bonded. Cracks shooting out in front of you are a clear sign you’ve found one of these unstable drifts and should stop to assess before getting onto steep slopes. These wind drifts will be most problematic in the isolated spots where they have formed slabs above weak layers buried 6-18” deep. Skiers on Blaze Mountain yesterday found this combination and triggered several thin avalanches in wind pillows below rocks (<a href="https://www.mtavalanche.com/images/22/fresh-wind-slab-near-summit-blaze…;). Snowmobilers in Teepee Basin also triggered two slides that broke a bit deeper (around 18”) on the same weak layer under a crust (<a href="https://www.mtavalanche.com/images/22/snowmobile-triggered-slides-teepe…;). These avalanches are good reminders to stay diligent about safe travel practices during LOW danger. Skiers in the northern Bridger Range yesterday also noted substantial loose snow sloughing that is worth&nbsp; watching for to avoid getting knocked off your feet, over a cliff, or into trees. Despite a long list of concerns, the avalanche danger is LOW today because large avalanches are unlikely.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Upcoming Education Opportunities

See our education calendar for an up-to-date list of all local classes. Here are a few select upcoming events.

March 4, Companion Rescue Clinic with the Bozeman Splitfest. Information and registration HERE.

2 snowmobile triggered slides in Tepee

Tepee Basin
Southern Madison
Code
SS-AMu-R1-D1.5
Latitude
44.91150
Longitude
-111.19400
Notes

Snowmobile triggered slides in Teepee Basin on 2/25/22.

From obs on 2/25/22: "18 inches of new snow from last week slid on top of crust layer.  The slide on the left was triggered by an uphill snowmobile hill climber, the slide on the right occurred when snowmobile turned out of a hill climb and his track broke through the crust layer causing everything with in his up and downhill track to slide."

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
1
D size
1.5
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

From obs on 2/25/22: "18 inches of new snow from last week slid on top of crust layer.  The slide on the left was triggered by an uphill snowmobile hill climber, the slide on the right occurred when snowmobile  turned out of a hill climb and his track broke through the crust layer causing everything with in his up and downhill track to slide."

Southern Madison, 2022-02-26

Thin wind slab on Blaze Mtn.

Northern Madison
Code
HS-AS-R1-D1
Latitude
45.36880
Longitude
-111.41200
Notes

Small skier triggered slides on Blaze Mountain.

From obs on 2/25/22: "I did get a couple new wind pillows to break and move somewhat forcefully while walking near the summit of Blaze, in an area with a very shallow snowpack. These were sitting on top of some large, old facets, and while they were relatively small, they definitely could have knocked me down in more consequential terrain."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Skier
R size
1
D size
1
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From obs on 2/25/22: "I did get a couple new wind pillows to break and move somewhat forcefully while walking near the summit of Blaze, in an area with a very shallow snowpack. These were sitting on top of some large, old facets, and while they were relatively small, they definitely could have knocked me down in more consequential terrain."

Photo: S. Reinsel

Northern Madison, 2022-02-26

Blaze Mountain obs

Date
Activity
Skiing

I did a loop out to Blaze Mountain via Beehive today, and don’t have a whole lot to report. I observed a few small, old sloughs and an east-facing cornice that failed lower down in Beehive, but none of them produced much. There is a noticeable wind crust at the surface in most places, which made the ski conditions humbling. 
I did get a couple new wind pillows to break and move somewhat forcefully while walking near the summit of Blaze, in an area with a very shallow snowpack. These were sitting on top of some large, old facets, and while they were relatively small, they definitely could have knocked me down in more consequential terrain. 

Region
Northern Madison
Observer Name
Sam Reinsel