GNFAC Avalanche Forecast for Sat Feb 29, 2020
<p>While today is Leap Day it feels more like <a href="https://en.wikipedia.org/wiki/Groundhog_Day_(film)">Groundhog Day</a>. It’s like we’re stuck in a loop. Every day this season we’ve warned you about the weak snow at the ground. Today is no different. That weak snow is still there and it is still a problem.</p>
<p>On Thursday night, a snowmobile trail groomer was up Swan Creek in the northern Gallatin Range and triggered an avalanche that broke 2-3’ deep, 100’ wide, and ran 600’ on a west facing slope at 7800’ (<strong><a href="https://www.youtube.com/watch?v=mpWviZprZZM&feature=emb_logo">video…;, <strong><a href="https://www.mtavalanche.com/node/22269">photo and details</a></strong>). It pushed the groomer 100’ off the road, rolling it and partially burying it. The vehicle protected him and the operator was unharmed. A skier or snowmobiler wouldn’t have been as lucky. This avalanche broke on the weak, sugary, faceted snow at the ground. It is easier to affect the weak layer and trigger an avalanche on thinner slopes, but avalanches on slopes with a deeper snowpack will be larger. Neither is a good recipe. After a couple days without loading, slopes aren’t on a hair trigger. However, this slide and natural avalanches that broke mid-week near Divide Peak in Hyalite (<strong><a href="https://www.mtavalanche.com/node/22293">photos and details</a></strong>) and in the Hourglass Chute in the Bridger’s (<strong><a href="https://www.mtavalanche.com/node/22257">photos and details</a></strong>) demonstrate that dangerous slides are still possible if you find just the wrong spot.</p>
<p> “Never trust a depth hoar snowpack” is an adage among avalanche professionals. This season is demonstrating the truth of that phrase. Stay conservative to stay safe.</p>
<p>Human triggered avalanches are possible and the avalanche danger is rated MODERATE.</p>
<p>Triggering a large avalanche is unlikely near Cooke City and West Yellowstone. A number of small avalanches broke in thin wind drifts near Cooke City earlier this week, but with warm temperatures they will mostly be glued on at this point (<strong><a href="https://www.mtavalanche.com/images/20/snowmobile-triggered-wind-slab-ne…;, <strong><a href="https://www.mtavalanche.com/images/20/small-wind-slab-near-cooke">photo…;). A big collapse on Thursday at Specimen Creek is a reminder that while very unlikely (we’re several weeks out from the last large avalanche), avalanches breaking at the ground still deserve a spot in the back of your mind (<strong><a href="https://www.mtavalanche.com/node/22267">details</a></strong>, <strong><a href="https://youtu.be/9g-x7o56ek8">video</a></strong>, <strong><a href="https://youtu.be/2IzNvRo0R3w">video</a></strong>). The avalanche danger is LOW today.</p>
<p>If you get out, please send us your observations no matter how brief. You can fill out an <strong><a href="https://mtavalanche.us17.list-manage.com/track/click?u=6653a830e4819c9e…; target="_blank">observation form</a></strong>, email us (<strong><a href="mailto:mtavalanche@gmail.com" target="_blank">mtavalanche@gmail.com</a></strong>), leave a VM at 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.
COOKE CITY
Every Friday and Saturday, Snowpack Update and Rescue Training. Friday, 6:30-7:30 p.m. at the Soda Butte Lodge. Saturday anytime between 10-2 @ Round Lake.
BOZEMAN
Natural avalanche in Divide Cirque
Timing uncertain, but the avalanche occurred sometime after the last significant snowfall on Tuesday 2/25/2020.
From observation: "Saw this avalanche that broke on a NW facing slope around 9300’. Looks to have failed on the facets at the ground ... the crown was 4-5’."
"Saw this avalanche that broke on a NW facing slope around 9300’. Looks to have failed on the facets at the ground ... the crown was 4-5’."
Photo: M. Murray
"Saw this avalanche that broke on a NW facing slope around 9300’. Looks to have failed on the facets at the ground ... the crown was 4-5’."
Photo: M. Murray
Forecast link: GNFAC Avalanche Forecast for Sat Feb 29, 2020
Overview of an avalanche triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. Photo: GNFAC
Crown of an avalanche triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. It broke 2-3' deep on weak sugary snow near the ground. It was on a West aspect at 7,500' elev., 100' wide, 600' long. Photo: GNFAC
An avalanche triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. The debris piled 8' deep on the road, which creates a terrain trap. Photo: GNFAC
Debris and groomer in an avalanche triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. Photo: GNFAC
Forecast link: GNFAC Avalanche Forecast for Sun Mar 1, 2020