21-22 | Gallatin National Forest Avalanche Center

From obs (12/5/21): "Went poking around in the Taylor Hilgard today looking for snow. As expected, found a thin and faceted snowpack at lower elevations. Snowpack improved considerably above 8500', often .5-1m. I dug a quick pit to the ground on a N-NE facing slope at around 9300'. Pit measuded 1.1m, and to my surprise consisted of a relatively compacted and consolidated snowpack, almost entirely 4f hardness. I was expecting to find layers of facets near the base of the snowpack, and between crusts in the middle, but did not."

Photo: L. Heine

Southern Madison, 2021-12-06

Access other image sizes:

GNFAC Avalanche Forecast for Mon Dec 6, 2021

Snowpack and Avalanche Discussion

Strong west winds drifted this weekend’s new snow into cohesive slabs that broke in small avalanches. Yesterday, multiple small wind slab avalanches were triggered while climbers approached ice climbs in Hyalite (<a href="https://www.mtavalanche.com/images/21/ice-climbing-avalanche"><…;, <a href="https://www.mtavalanche.com/images/21/small-avalanche-hyalite">…;). These drifts can still be triggered today. As more snow falls new drifts will form and the number of places you can trigger a slide will increase. These drifts of new snow are the primary concern today and through this next storm. Carefully assess the snowpack and consider the consequences of a slide before exposing yourself to steep, recently wind-loaded slopes. Cracks shooting out in front of you are bullseye data that you’ve found an unstable drift.

On higher elevation shady slopes a 1-2 ft deep layered snowpack has developed. On Saturday, as Dave and Alex put up the Flanders Mt. Weather Station in Hyalite, they started out on dirt at the trailhead but up high they found several feet of snow including weak layers that broke in stability tests (<a href="https://www.youtube.com/watch?v=ovtaZJ04WpE">video</stro…;). We have received reports of these weak layers across the advisory area (<a href="https://www.mtavalanche.com/sites/default/files/styles/very_large_1200w… 1</a>, <a href="https://mtavalanche.com/images/21/shallow-snowpack-bridger-range"><stro… 2</a>, <a href="https://youtu.be/oF8q1tMQuh8">video</a> from Cooke City) and in nearby ranges (<a href="https://www.mtavalanche.com/images/21/shallow-snowpack-9200-ft-emigrant… of snowpack on Emigrant</a>, <a href="https://www.mtavalanche.com/images/21/faceted-snow-under-wind-board-970… 2</a>). As more new snow piles up, avalanches will start breaking on these weak layers. Dig down and search for these weak layers on any slope with continuous snow cover.

We appreciate all the observations we have already received this season. You are helping us develop a more complete understanding of this season’s snowpack! Please submit observations <a href="https://www.mtavalanche.com/node/add/snow_observation">here<…;

If you have avalanche, snowpack or weather observations to share please submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation">websi…;, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</str…;), phone (406-587-6984), or Instagram (#gnfacobs).

Read more about GNFAC Avalanche Forecast for Mon Dec 6, 2021

Upcoming Education Opportunities:

Get your avalanche brain ready for the season at one of the many classes listed on our education calendar, and list of upcoming events below. Don’t delay preparing and inspecting your avalanche gear. Get some tips from Dave Zinn in this Pre-Season gear check video.

Read more about Ice Climbing Avalanche

This post and picture was on the FB ice climbers page. This is from Comet Alley, a steep gully off the East Fork Road:

Today we found that this gully has some significant loading. We triggered a few wind slab slides on the approach. We managed to get a quick lap on the route and got out before it got loaded more. TBH with more unconsolidated snow I’d reconsider going there.