22-23

GNFAC Avalanche Forecast for Sat Dec 31, 2022

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Triggering large avalanches is a serious possibility today. You could trigger an avalanche within the snow that’s fallen over the last week, on a weak layer buried just beneath that, or deep in the snowpack (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=AzCUIW7Fr_0"><span><span><span><strong>… Fork video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Continued loading every day this last week by new snow and wind drifting has kept stressing the weak layers and building thicker and more cohesive slabs of fresh snow. In general, the snowpack has been able to keep up and accommodate the loading. Triggering slides has become slightly less likely, but by no means does that mean conditions are safe. While the likelihood has gone down a little bit, the potential size and destructive power has not decreased.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>As Alex identified in yesterday’s video from Cooke City, wind loaded slopes are where you’re most likely to trigger a slide today (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=g1dr_mAdKzM&amp;list=PLXu5151nmAvTi1DBS… City video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Steering clear of wind drifts altogether would be a wise call. Watch for signs of instability in the new snow, such are shooting cracks, collapses or recent avalanches. Assessing the deeper weak layers will be harder. Snowpack tests aren’t necessarily going to give you actionable information. For now, simply don’t trust those deeper weak layers. Tone down your objectives appropriately for the possibility of triggering large, deep slides (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27382"><span><span><span><span><span><… triggered hard slab at Big Sky Resort</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><span><span><span>If you’re considering riding steep slopes today, ponder this analogy: as we’ve gotten a few days out from the last rapid loading event (which hit particularly hard in the southern areas) we’ve removed a couple bullets from the gun you’re playing russian roulette with. But the gun’s still got at least one bullet left. Is that really a game you want to play today? As an alternative, mellow slopes (less than 30 degrees steep) will hold good riding conditions without the risk.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Human triggered avalanches remain possible and the avalanche danger is MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).&nbsp;</span></span></span></span></span></span><span><span><span><span><span><span>&nbsp;</span></span></span></span></span></span></p>

<p>Triggering large avalanches is a serious possibility today. You could trigger an avalanche within the snow that’s fallen over the last week, on a weak layer buried just beneath that, or deep in the snowpack. Steering clear of wind drifts altogether would be a wise call. Tone down your objectives appropriately for the possibility of triggering large, deep slides.</p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.

West side bridgers

Date
Activity
Skiing

Went to jones creek yesterday, 20 cm facets underneath everything it seems. Depth where the wind could reach it(sw aspects mostly) was averaging 60 cm, 100 to 120 cm where it was more protected. Not a lot of weight yet but columns failed on isolation. No cracking or whumphing

Region
Bridger Range
Location (from list)
Truman Gulch
Observer Name
Pat Hinz

snowmobile triggered avalanche Frog Pond Basin

Butte Area
Code
AM
Latitude
46.03950
Longitude
-113.79200
Notes

Snowmobile club members texted me that they triggered a 3' deep slab, that ran 100 yds., from connected terrain in Frog Pond Basin.  It sounded like a heavily wind loaded slope.     

Number of slides
1
Number caught
0
Number buried
0
Trigger
Snowmobile
Slab Thickness
90.0 centimeters
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

natural avalanche McDermott Hill in the Flint Range

Flint Creek Range
Butte Area
Code
N
Latitude
46.32370
Longitude
-113.10200
Notes

Natural avalanche from the top of the popular snowmobile climbing spots on McDermott Hill in the Flint Range near Philipsburg.  There have been several close calls and a fatality in this same path.  It is named for the person who was killed in an avalanche there in the 70s.  It appeared to be a wind load on the ridge that initiated the slide.  In the background of a janky video, it appears there were other naturals as well.  The slide ran an estimated 800 ft, but no other information was obtained.

Number of slides
1
Number caught
0
Number buried
0
Trigger
Natural trigger
Vertical Fall
800ft
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

natural avalanche McDermott Hill in the Flint Range

Date
Activity
Snowmobiling

Natural avalanche from the top of the popular snowmobile climbing spots on McDermott Hill in the Flint Range near Philipsburg.  There have been several close calls and a fatality in this same path.  It is named for the person who was killed in an avalanche there in the 70s.  It appeared to be a wind load on the ridge that initiated the slide.  In the background of a janky video, it appears there were other naturals as well.  The slide ran an estimated 800 ft, but no other information was obtained.

Region
Butte Area
Location (from list)
Flint Creek Range
Observer Name
Will Shoutis