21-22

GNFAC Avalanche Forecast for Sun Jan 30, 2022

Snowpack and Avalanche Discussion

<p>The snowpack is generally stable and avalanches are unlikely, but unlikely does not mean impossible. Small avalanches of wind-drifted snow or loose snow could be triggered and are most hazardous in high consequence terrain where they could push you over cliffs or into trees. There are isolated areas where a slab of wind-drifted snow could produce an avalanche large enough to bury or injure a person. Yesterday skiers near Big Sky saw a natural avalanche on Wilson Peak which involved recent, wind-drifted snow and appeared to be triggered by a cornice fall on Friday (<strong><a href="https://www.mtavalanche.com/node/25668">photo and details</a></strong>). If you choose to ski or ride in avalanche terrain it is always important to carefully assess the snowpack on each slope, only expose one person at a time, and carry proper avalanche rescue gear.</p>

<p>Yesterday Ian rode all over north of Cooke City, he did not see any avalanches and found stable snow. I saw similar stable conditions near Lionhead, but we both saw that the top of the snowpack has become a pile of weak layers (<strong><a href="https://www.mtavalanche.com/images/22/weak-layers-lionhead">photo</a></…;, <strong><a href="https://www.youtube.com/watch?v=gR0EiO4JEeM&amp;list=PLXu5151nmAvT1nrM2… video</a></strong>, <strong><a href="https://www.youtube.com/watch?v=7pv0tDJMuK4&amp;list=PLXu5151nmAvT1nrM2… video</a></strong>). We expect avalanches will break on these layers when we get enough snow. We have found similar weak layers on the surface of the snowpack throughout the advisory area over the last week (<a href="https://www.youtube.com/watch?v=VjIW7Pp-hz0"><strong>Mt. Ellis video</strong></a>, <a href="https://www.youtube.com/watch?v=SAKP0a0G9ks"><strong>Saddle Peak video</strong></a>, <a href="https://www.youtube.com/watch?v=6ax6l1PhUb0"><strong>Wheeler Mtn. video</strong></a>, <strong><a href="https://www.youtube.com/watch?v=I6AleixLxTI&amp;list=PLXu5151nmAvT1nrM2… Fork video</a></strong>). While these are not a problem right now, we want to have them in mind and be ready to ride in safer terrain if we get enough snow to create unstable conditions.</p>

<p>Today, the snowpack is generally stable with only small or isolated instabilities, and the avalanche danger is LOW.</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>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

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Natural cornice triggered slide SW gully of Wilson Peak

Wilson Peak
Northern Madison
Code
SS-NC-R2-D2
Latitude
45.32700
Longitude
-111.32500
Notes

From obs 1/29/22: "Avalanche appeared to have been caused by a breaking cornice on lookers left. Probably from Friday"

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Cornice fall
R size
2
D size
2
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From obs. 1/29/22: "Avalanche appeared to have been caused by a breaking cornice on lookers left. Probably from Friday [1/28]." Photo: A. Pfaffinger (zoomed in from original photo)

Northern Madison, 2022-01-30

From obs 1/29/22: (from outside advisory area) "Saw a snowmobiler trigger a wind slab avalanche of an east facing slope near the head of the Weatherwax Creek drainage on Kings Hill. The rider was not caught. Despite a recent 18" snowfall reported by Showdown, there was almost no snow left on the trail above the slope due to high winds. The crown appeared to be 12-18" deep and about 100 feet wide, and the slide ran about 300 feet." Photo: C. Mozol

Out of Advisory Area, 2022-01-30

We rode at Lionhead today (Jan. 29, 2022) and found very weak snow on the surface which is not a problem now, but will be when we get more snow. Photo: GNFAC

Lionhead Range, 2022-01-29