22-23
"On Saturday (2/25/23)... On the southwest ridge of Mineral Mountain we observed a large slide, approximately 200ft wide, that appeared to trigger another slide lower down on the slope." Photo: E. Schreier
Buck ridge, new snow and wind
We rode on Buck Ridge today to do some maintenance on our RAWS station for the fire folks and check on the yellow mule cabin. Where the wind hadn't blown it away yet, there was 4" of snow from over night on top of very firm snow, likely from the last round of wind. The most sheltered areas behind trees and down in the basins still had some deeper, soft snow and better riding. We saw one small wind slab avalanche in the new snow above Beaver Creek on a north aspect.
Unstable results on wind load
I toured up to hyalite lake today to check out how the west facing walls in the main fork of hyalite (hyalite lake drainage ) were stabilizing after last weeks wind. On Friday I noticed “Provo’s run” (large path near overlook mtn) slid from the top which appeared to have slid due to the heavy wind loading. The slid looked to be about 24” deep and ran full path . So today I checked out the west facing walls close the hyalite lake and around 9500’ the upper sections of these slid paths were wind effected and unstable, and I did not ride them
I dug a pit around 9500’ on the west facing wall near the lake and got unstable results. ECTP 11 which propagated below the recent wind load from last week.
the snow pack is 240 cm deep and is nice and consolidated without any major layers on several of the pits I dug at several elevations on these upper elevation west facing walls accept for the wind load on the upper elevations pits
Possible remote trigger by wildlife
Deep Slab Low Elevation Phillipsburg
Possible remote trigger by wildlife
GNFAC Avalanche Forecast for Mon Feb 27, 2023
<p><span><span><span><span><span><span>Near Cooke City, the last couple days there were multiple natural and human-triggered avalanches with a few people caught, and luckily nobody injured. Yesterday two skiers triggered and were carried by a 2 foot thick slab of wind-drifted snow (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28338"><span><span><span><strong><span… and details</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). On Saturday, a large natural avalanche buried the Daisy Pass road (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28305"><span><span><span><strong><span… and details</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>), a skier triggered and was caught in an avalanche near Round Lake (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/skier-triggered-slide-near-round-…;), and a snowmobiler was partially buried on Mt. Abundance (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28331"><span><span><span><strong><span…;). Over the weekend large natural avalanches were also seen on Henderson Mountain (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/natural-avalanche-e-henderson-ben…;), in Sheep Creek (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/natural-avalanche-sheep-creek-lar…;) and Republic Creek (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/large-natural-avalanche-east-aspe…;). On Saturday, in the southern Gallatin Range skiers intentionally triggered a small wind slab (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28319"><span><span><span><strong><span…;), and at Lionhead a rider saw recent avalanches on wind-loaded slopes (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/avalanches-wind-loaded-slopes-lio…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Strong winds drifted last week’s 2-4 feet of snow into thick slabs. Recent widespread avalanche activity is a sign these wind slabs remain likely for a person to trigger. Today’s 5-6” of new snow will be drifted into fresh slabs that will add weight and may cause deeper avalanches to be triggered or break naturally. Avoid travel across steep wind-loaded slopes and minimize time spent below them. On non-wind loaded slopes, carefully assess the stability of new snow and dig to look for potential weak layers. The avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on other slopes.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The mountains near Bozeman and Big Sky received 2-5” of new snow equal to 0.2-0.3” of snow water equivalent (SWE). Moderate west-southwest wind will drift the new snow into thicker slabs that are possible to trigger. On Friday there were natural and human-triggered slides reported near Big Sky and Hyalite (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28293"><span><span><span><strong><span… triggered on Buck Ridge</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/large-natural-wind-slab-mt-blackm… on Mt. Blackmore</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/natural-cornice-collapse-beehive"… fall Beehive</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28325"><span><span><span><strong><span… on Fan Mtn.</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Today, the main concern will be drifts of newly fallen snow, but the possibility exists to trigger a deeper avalanche below drifts of last week’s snow.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Be cautious of wind loaded slopes which are often found below cornices, convex rolls and on the opposite side of scoured ridgelines. If you plan to ski or ride steep slopes, choose slopes that do not have fresh drifts and dig down a couple feet to assess stability of last week’s wind-drifted snow. Watch for cracking across the snow surface around your feet or skis as a sign the new snow is unstable. Today the avalanche danger is MODERATE because human-triggered avalanches are possible.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>In Island Park, heavy snowfall and strong winds create fresh, unstable slabs. These wind slabs will be easy to trigger and could break naturally. Recently formed wind slabs from last week are also possible to trigger. Identify and avoid steep, wind-loaded slopes.</span></span></span></span></span></span></p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
Photo: B. Fredlund 2/26/23
Forecast link: GNFAC Avalanche Forecast for Mon Feb 27, 2023
From 2/26/23: "Today we toured to a ridge across from the west face of Republic Mountain. We observed multiple natural avalanches on several aspects. Winds were calm until around noon, and then picked up in the afternoon and were heavily loading north aspects at this location." Photo: E. Schreier
Forecast link: GNFAC Avalanche Forecast for Mon Feb 27, 2023