Alex Marienthal stands near the 2-4 foot thick crown. The bed surface was an icy mass on the ground. Photo: GNFAC
17-18
A snowmobile set off a huge avalanche up Mill Creek in the Tobacco Root Mtns. Slid on a weak layer near the ground surface. Photo: C. Atkinson
A snowmobile set off a huge avalanche up Mill Creek in the Tobacco Root Mtns. Slid on a weak layer near the ground surface. Photo: C. Atkinson
GNFAC Avalanche Forecast for Wed Jan 3, 2018
Snowpack and Avalanche Discussion
<p><u>Let us recap</u>: The mountains got 2-4’ of snow by Saturday evening resulting in many natural and human triggered avalanches. On Saturday we issued an Avalanche Warning and there was a High danger in all ranges. Avalanches were failing on weak, faceted snow either on the Thanksgiving crust or under the storm snow buried 2-4’ deep. Many slides occurred on lower elevation slopes that have a shallow, weak snowpack. Since Saturday, the weather improved, visibility has been perfect, the snow is deep and everyone hit slopes with abandon, some losing their minds in the process and many getting extremely lucky.</p>
<p>The snowpack is stabilizing quickly, but not on all slopes, and not equally. You have to assess each slope individually, which means digging and doing a stability test in the absence of collapsing or cracking. Eric was in Cooke City yesterday and saw more avalanche crowns in one day than ever before. His <strong><a href="https://youtu.be/s9mow9v69rs">video</a></strong> at the crown of an avalanche explains what happened and why stability is improving. Yesterday my partner and I skied above Hebgen Lake and got large collapses on my way up, but none up high in the big starting zones, and my stability tests were on the poor side (<strong><a href="https://youtu.be/5yXaQvWxJZI">video</a></strong>).</p>
<p>Today, I do not expect to see natural avalanches, but human triggered ones are possible and the danger is rated <strong>MODERATE</strong>, a “spicy” moderate is what I called it in yesterday’s video. Spicy because although the likelihood of triggering an avalanche fits a moderate rating, I’m being conservative and traveling as though it’s rated considerable.</p>
<p>If you get out and have any avalanche or snowpack observations to share, drop a line via our <a href="https://www.mtavalanche.com/node/add/snow_observation">website</a>, email (<a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a>), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Upcoming Avalanche Education and Events
BOZEMAN
TONIGHT, Jan. 3, Avalanche Awareness, 6-7 p.m. at REI Bozeman
Jan. 12 and 13, Companion Rescue Clinic, Info and Register
From an email of the two who were caught in the slide:
Google Earth view of Warm Creek Avalanche. Map shows approximate area of avalanche which caught two skiers and partially buried one.
From e-mail: "On 12/29 we parked about 2 miles west of Silvergate and skied a mile west on the road and turned north to the ridge just NE of Baronette pk. We were aware of high avalanche danger but somehow got complacent on our surroundings and ended up getting caught in this slide. The crown was 2-3 feet high and propagated well into the timber on the "Thanksgiving crust"
Warm Creek Avalanche crown near Cooke City. 2 skiers were caught while traversing, and one was partially buried.
From e-mail: "On 12/29 we parked about 2 miles west of Silvergate and skied a mile west on the road and turned north to the ridge just NE of Baronette pk. We were aware of high avalanche danger but somehow got complacent on our surroundings and ended up getting caught in this slide. The crown was 2-3 feet high and propagated well into the timber on the "Thanksgiving crust"