19-20

This 2-foot deep snowpit consisted of layers of crusts and facets. It was dug on a SW aspect at 9800' in Miller Drainage. Nothing broke clean in our stability tests and we are optimistic about it handling a load of new snow. Photo: GNFAC

Snowpit profile is here.

Cooke City, 2019-11-27

GNFAC Avalanche Forecast for Mon Nov 25, 2019

Snowpack and Avalanche Discussion

<p>Snow depth is 1-3 feet throughout the advisory area. There is minimal evidence of widespread buried weak layers (<strong><a href="https://www.mtavalanche.com/snowpits">snowpits</a></strong&gt;), and avalanche activity has been mostly small slides confined to new snow (<strong><a href="https://www.mtavalanche.com/avalanche-activity">avalanche log</a></strong>). Aside from the couple inches of snow in Big Sky last night, the last snowfall was 4-6” five days ago (<strong><a href="https://www.mtavalanche.com/weather/wx-avalanche-log">weather log</a></strong>). Over the last couple days strong winds drifted recent snow into fresh slabs along ridgelines (<strong><a href="https://www.mtavalanche.com/sites/default/files/styles/very_large_1200w…;). Skiers in Hyalite found these fresh wind slabs which&nbsp;cracked easily under their skis, and they adjusted their plans to avoid terrain with big consequences (<strong><a href="https://www.mtavalanche.com/sites/default/files/styles/very_large_1200w…;). Avoid steep slopes with evidence of fresh wind-loading and be extra cautious of terrain where a slide can carry you into rocks, trees or over cliffs.</p>

<p>Where the snowpack is shallower, such as the mountains near West Yellowstone and the southern Madison and Gallatin ranges, there are weak layers of sugary facets on the ground (<strong><a href="https://www.youtube.com/watch?v=i6DWvLU0Eks&amp;list=PLXu5151nmAvSbcbVf…;, <strong><a href="https://www.mtavalanche.com/sites/default/files/styles/very_large_1200w…;). For now, these weak layers make larger avalanches a concern only on heavily wind-loaded, shady high elevation slopes (<strong><a href="https://www.mtavalanche.com/node/21027">photos</a></strong&gt;, <strong><a href="https://www.mtavalanche.com/sites/default/files/styles/very_large_1200w…;). When these mountains receive more snowfall, possibly later this week, the snowpack could become very unstable on all steep slopes.</p>

<p>Check out our <strong><a href="https://www.mtavalanche.com/forecast/bridgers">regional conditions</a> </strong>pages, <strong><a href="https://www.mtavalanche.com/snowpits">snowpits</a></strong&gt;, and <strong><a href="https://www.mtavalanche.com/weather/wx-avalanche-log">weather log</a> </strong>for detailed information specific to where you plan to travel. We are seeking more field data (and snowfall) before we issue daily danger ratings. If you'd like to help us you can quickly fill out an <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>observat… form</strong></a> and attach a picture or two. You can also email us (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), leave a message on our phone (406-587-6984) or Instagram (#gnfacobs).</p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out and plan to attend one or two: Events and Education Calendar.

BOZEMAN

Large avalanches in Absaroka - Outside Advisory area

Out of Advisory Area
Code
HS-N-R2-D2.5-U
Elevation
10000
Aspect
NE
Notes

Sometime last week (11/20-11/22) these large avalanches occurred on heavily wind loaded northeast facing slopes in the Absaroka. The snowpack there is thin and faceted, similar to the southern ranges and mountains near West Yellowstone. Photo: B. VandenBos

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
2
D size
2.5
Bed Surface
U - Unknown
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year