17-18

GNFAC Avalanche Advisory for Sun Nov 5, 2017

Snowpack and Avalanche Discussion

<p>Since Wednesday the mountains have received 2-3’ of new snow with Cooke City getting over 4’. At the lower elevations this fell onto dirt while up high there was already 1-2’ on the ground. Most field observations indicate that the snow has good stability, a nice treat for early November. The exception are slopes that have been wind-loaded near the ridgetops. Avalanches were seen on Thursday on Mt. Blackmore (<a href="https://www.mtavalanche.com/images/17/natural-avalanches-mt-blackmore-n…;) and <strong>if winds increase, so will the avalanche danger</strong>.</p>

<p>Skiers crawled all over the Bridger Range yesterday, mostly at Bridger Bowl. Eric and his partner joined the masses and observed, “We didn’t experience any cracking or collapsing and did not observe and recent activity. Overall stability was better than expected. I would guess on Saddle or the northern Bridgers things could be different where the wind had more influence.” His <strong><a href="https://youtu.be/fcRlhZKUlBQ">video</a></strong&gt; explains the layering in the snowpack. Skiers on Mt Blackmore in Hyalite found similar conditions and in both ranges the winds were light. Climbers in Hyalite wallowed in new, powder snow down to the rock (<strong><a href="https://www.mtavalanche.com/images/17/looking-ice-flanders">photo</a></…;) and only encountered sluffing.</p>

<p>It is early season and our understanding of the stability is limited since our field data is scarce. Besides the typical early season hazards of rocks, tree stumps, and our own rusty skill sets, we still have to analyze snow stability and travel as though it’s mid-winter (i.e. only expose one at a time, carry rescue gear, test for stability, etc.). There’s no shortcut to safety.</p>

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<p>If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a&gt;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Get Avalanche Smart – Growing Up

The Friends of the Avalanche Center present the first of 4 short films promoting avalanche education. Ben Goertzen explains why it is important to take an avalanche class. VIDEO.

Upcoming Avalanche Education and Events

Events and Education Calendar

Billings

7 November, Avalanche Awareness, 6-7:30 p.m. at Basecamp, Billings

BUTTE

GNFAC Avalanche Advisory for Sat Nov 4, 2017

Snowpack and Avalanche Discussion

<p>The equation is fairly simple today – lots of new snow combined with moderate to strong winds out of the west-southwest will significantly increase the avalanche hazard. Wind loaded slopes will be the most prone to producing natural and human triggered slides, but non-wind loaded slopes also pose a threat. On Thursday, skiers on Mt Blackmore in the northern Gallatin Range observed natural avalanches in steep, rocky terrain. These slides appeared to be the result of heavy wind loading <strong>(<a href="https://www.mtavalanche.com/images/17/natural-avalanches-mt-blackmore-n…;, <strong><a href="https://www.mtavalanche.com/images/17/crown-lines-mt-blackmore-nov-2">p…;). Today I expect both natural and human triggered avalanches to occur on similar slopes.</p>

<p>Despite heavy snow over the past few days, snow coverage and structure remains highly variable. On sun exposed slopes and lower elevation terrain, 1-2 feet of new snow is sitting on mostly bare ground. In these areas coverage is thin and the likelihood of triggering a larger slab avalanche is less likely. In higher elevation terrain, new snow is sitting over a variety of old snow surfaces. On some slopes, mainly those facing the north half of the compass, the new snow is poorly bonded to the old snow surface and has produced unstable results in stability tests (<a href="https://www.mtavalanche.com/images/17/clean-break-under-new-snow"><stro…;, </strong><a href="https://www.mtavalanche.com/images/17/snow-pit-near-cooke"><strong>phot…;, </strong><a href="https://www.youtube.com/watch?v=WfCdHe8cqu0&amp;list=PLXu5151nmAvQSYtIf…;). On other aspects, the new snow is well bonded to the old snow surface and stability is better.</p>

<p>Yesterday, Alex and his partner toured up Bridger Bowl and found relatively good stability near the top of the Bridger Lift. That story will likely be different today with another 8-10 inches of new snow overnight. <strong>The bottom is </strong>– all the necessary ingredients for avalanches exist in the mountains. Take the necessary time to <a>assess each slope carefully before hiking up or skiing down and pay attention to the terrain above and below you. It will likely be busy in the backcountry, especially around Bridger Bowl, so use good protocol when traveling around other people.</a></p>

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<p>If you get out and have any avalanche or snowpack observations to share, drop a line via our website, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a&gt;), phone (406-587-6984), or Instagram (#GNFACobs).</p>

New Avalanche Education Video

Check it out! The Friends of the Avalanche Center present the first of 4 short films promoting avalanche education. Ben Goertzen explains why it’s important to get avalanche education. VIDEO

Upcoming Avalanche Education and Events

Events and Education Calendar

Billings

7 November, Avalanche Awareness, 6-7:30 p.m. at Basecamp, Billings

BUTTE

This snowpit was dug near the top of the Apron at Bridger Bowl. The stability test score of ECT 9 means it propogated all the way across and slid quickly on the 9th tap. The weak layer was 30 cm from the surface in a 90cm snowpack. The interface between the old/new snow may remain unstable through the weekend, especially with wind-loading. Photo: Roy Taylor

 

Bridger Range, 2017-11-03