GNFAC Avalanche Forecast for Sat Mar 30, 2024
<p><span><span><span><span><span><span>Strong winds are drifting the close to 2 ft of recent snow into big, deep, fresh drifts that will be easily triggered today. Avoid steep slopes with these fresh wind drifts to avoid the most likely setup for triggering a large avalanche. With such strong winds, drifts may have formed in unusual locations, so stay on high alert. If the snow suddenly feels hollow and stiff you’ve found one of these drifts. Shooting cracks are bullseye data that the drift is unstable. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>In addition, if the sun wets the snow surface, wet loose avalanches will quickly become an issue and with so much soft new snow could be substantial enough to be problematic. We’re also not ready to forget about the possibility of triggering an even deeper slide on the early season weak layers.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on all other slopes.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Winds are much lighter across the rest of the advisory area and there is less new snow. While there are a wide range of concerns today, we don’t expect widespread avalanching.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The number one concern to watch out for is unstable wind drifts. With winds shifting direction over the last couple days these drifts could be found on any aspect. Many drifts will have bonded well, but digging down to confirm they have is a good idea. Especially because, as Alex found yesterday in the Taylor Fork, in some places there is a newly buried weak layer under these drifts (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31674"><span><span><span><span><span><…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The new snow will easily sluff if the sun and warm temperatures combine to make the surface wet for the first time. Be heads up if you feel the snow start to get sticky and begin to see rollerballs and pinwheels.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The final concern is avalanches breaking on the weak layers at the bottom of the snowpack. Yesterday, skiers on Mt. Blackmore saw a deep avalanche that broke within the last couple days (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31672"><span><span><span><span><span><… and photos</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>). It’s hard to tell from the photos exactly where in the snowpack it broke, but it doesn’t really matter, it’s a good reminder that there is still a possibility of triggering deep slides and that should factor into your terrain choices today. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE near Bozeman, Big Sky, West Yellowstone, and Cooke City.</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.
New snow avalanche concerns
We rode into Taylor Fork, to the ridge at sunlight basin, through Carrot basin to the wilderness boundary, and back along the ridge to Beaver slide. There was 12" of new snow equal to 1.25" SWE.
Wind was calm, and skies were partly sunny with clouds obscuring Sage Peak, Skyline and areas to the south. The recent snow had not been affected by wind anywhere. The ridge near the weather station that is normally scoured still had 8"+ of light new snow on it. Sunny slopes got moist in the afternoon.
The only new avalanche I saw was one slope with small debris from a loose snow slide/ or new snow/wind slab on Kirkwood Ridge.
We dug a pit near the wilderness boundary where Ian and Dave dug earlier in the week. We had ECTP13 and ECTP18 on the recently buried layer of small facets below a 2" crust under the 12" of new snow.
Spring Variability in Hyalite
Skied Hyalite and Divide peak today. Snow conditions were extremely variable, ranging from undisturbed powder, to wind slabs and sun crusts. No bullseye signs of instability outside of the new snow (i.e. on the deep slab layer).
In the recent snow there was some localized cracking in dispersed windslabs, rollerballs coming off steep solar aspects, and two old windslab releases in the summer trail bowl off Hyalite. These slides probably released either before or during the most recent wind/storm event, as the start zones were both partially refilled. The larger of the two was noticeably older than the other, with the start zone and debris deeply covered. Both were R1/D1, naturally triggers, with crowns no deeper than half a meter directly under the cornice. No cornice fall seemed evident near either crown.
New snow that was sheltered from the wind and sun showed no signs of instability, and the weather consisted of light winds with periods of interspersed graupel and sun. Weather and obvious wind affects looked similar across the range.
Natural avalanche on Mt. Blackmore
From obs: "Spotted this big guy on the east face of Blackmore today. Seemingly natural and I believe it occurred in the last 36 hours or so. Debris had last nights snow on it. I’d estimate it at D2. "
From obs: "Spotted this big guy on the east face of Blackmore today. Seemingly natural and I believe it occurred in the last 36 hours or so. Debris had last nights snow on it. I’d estimate it at D2." Photo: E. Heiman
Forecast link: GNFAC Avalanche Forecast for Mon Apr 1, 2024
From obs: "Spotted this big guy on the east face of Blackmore today. Seemingly natural and I believe it occurred in the last 36 hours or so. Debris had last nights snow on it. I’d estimate it at D2. " Photo E. Heiman
Forecast link: GNFAC Avalanche Forecast for Sat Mar 30, 2024GNFAC Avalanche Forecast for Sun Mar 31, 2024
Hyalite Peak Slide
From obs: "Spotted two fresh natural slides, one within Divide cirque on a NE aspect @ ~9,800 (D1, R1), and another on the N face of Hyalite @ ~10,200ft. that was mostly out of view, but could be estimated around similar size and destructiveness. These seem to have occurred within the last 24 hours, or after snowfall, likely windslabs on lee slopes."
Divide Cirque Slide
From obs: "Spotted two fresh natural slides, one within Divide cirque on a NE aspect @ ~9,800 (D1, R1), and another on the N face of Hyalite @ ~10,200ft. that was mostly out of view, but could be estimated around similar size and destructiveness. These seem to have occurred within the last 24 hours, or after snowfall, likely windslabs on lee slopes."
Skiers on 03/29/2024 saw this avalanche on the N face of Hyalite Peak from Divide Cirque. This avalanche likely occurred in the last 24 hours. Photo: E. Webb