GNFAC Avalanche Forecast for Mon Apr 25, 2022
<p>This weekend’s storm was one of the larger storms of the season. In Hyalite, it was <em>the largest storm</em> of the season (with 2.5” of snow water equivalent). With so much fresh snow, there were many avalanches, both human triggered and natural (see the <a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><u>avalanche log</u></a> for a surely incomplete list). Avalanches were remotely triggered (<a href="https://www.mtavalanche.com/node/26522"><strong><u>details</u></strong>…;) and caught and carried skiers (<a href="https://www.mtavalanche.com/node/26536"><strong><u>details</u></strong>…;). The new snow has now had some time to stabilize, so it won’t be so wildly unstable today, but you could still trigger a slide. Watch for cracks shooting in front of you as signs that the new snow is unstable. The hazard will linger longest on shady, high elevation slopes where the snowpack stays the coolest. Digging down to test the interface between the new and old snow will let you know if you’ve found a slope where you could still trigger a slab avalanche.</p>
<p>The major hazard has now shifted to wet snow concerns. Strong late spring sun and temperatures well above freezing will quickly destabilize the new snow. With so much new snow, loose avalanches could pick up a lot of volume and be very dangerous. Plan to avoid steep sunny slopes as they warm up. Conditions will change rapidly, so if you see and feel the snow surface getting wet, don’t delay. Quickly move to lower angled terrain. </p>
<p>As it gets cloudier and a little cooler later in the week and further out from the big storm, the avalanche hazard will generally decrease. However, there may be a little bit of new snow, in which case, newly formed wind drifts will be a concern. If it does snow, watch out for those wind drifts, particularly in very steep, high consequence terrain. </p>
<p>This week’s weather will be classic Montana spring weather, with a little bit of everything - sun, clouds, warm temps, and maybe some rain or snow. This means you’ll need to be ready for anything. That means carrying rescue gear (beacon, shovel & probe), traveling with a partner, and watching for signs of instability is essential. </p>
<p>We will issue spring snowpack and weather updates each Monday and Friday through April and we will share relevant avalanche and snowpack information on our website and social media. If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong><u>websi…;, email (<a href="mailto:mtavalanche@gmail.com"><strong><u>mtavalanche@gmail.com</u></str…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Announcements, Avalanche Education and Events
Bridger Bowl is closed, and backcountry conditions exist. There is no avalanche mitigation or ski patrol rescue. In case of emergency, call 911. Please stay clear of work areas, snowmobiles, chair lifts and other equipment. Without the daily avalanche mitigation efforts of the ski patrol, backcountry conditions now exist within the boundaries of Bridger Bowl (video).
Large natural near Daisy Pass
Riders observed a large natural avalanche near Daisy Pass.
Two skiers caught and carried in Beehive
Skiers caught and carried in 4th of July Couloir, in Beehive Basin on Friday, April 22nd.
From email: "just under the top of the couloir, my partner noted that the new snow
had become much denser, an observation I did not register. Immediately after making this observation,
he watched a crack propagate from his ice axe, upslope and to the left about twenty feet. In response,
he shouted and attempted to self-arrest, but was unable to resist the moving snow and was pushed
over backwards. I was immediately behind him as this happened and noted the moving snow around me
as he called out. I’m not entirely sure how, but I managed to move sideways, out of the moving snow,
before I had been carried through the constriction in the couloir. As I stood up, I watched as my partner
was carried out of the couloir and about halfway down the bowl beneath it, what I would estimate to be
100-200 yards."
Collapsing and rain crust
Recent wet storm with overnight freeze produced a crust up to 8,000’ +\-…above that was dense but soft snow atop a thin snowpack (50cm)
Experienced collapsing and shooting cracks of wind loaded snow near the ridge of Shafthouse Hill.
Loose snow avalanches on sun affected steep terrain
Natural and Skier Triggered Avalanches near Schlasman's
A skier sent a video showing many new snow avalanches around the Schlasman's Lift.
Natural Slab Avalanche near Cooke City
From email: "I'd hypothesize that this avalanche might have happened sometime yesterday. There was a light rain event on April 21, and an associated widespread (but minor) wet loose avalanche cycle on steep northerly aspects the same day. And it appears from the photo that the slab avalanche might have happened subsequent to all the rollerball/ well loose activity. Yesterday was very warm here also, with a high of 47 deg F at the NE Entrance at noon."
From email: "I'd hypothesize that this avalanche might have happened sometime yesterday. There was a light rain event on April 21, and an associated widespread (but minor) wet loose avalanche cycle on steep northerly aspects the same day. And it appears from the photo that the slab avalanche might have happened subsequent to all the roller ball/ well loose activity. Yesterday was very warm here also, with a high of 47 deg F at the NE Entrance at noon." B. Fredlund
Forecast link: GNFAC Avalanche Forecast for Mon Apr 25, 2022GNFAC Avalanche Forecast for Fri Apr 29, 2022
Skier Triggered Slide Avalanche Gulch
A pair of skiers ski cut the main chute of Avalanche Gulch. It propagated widely and ran approximately 800' vertical.
Skier Triggered Mad Man's Repeat
A group skied Manman's and triggered the upper chute. When the initial avalanche hit the fan the slide propagated wider and ran "Well past the North Bowl Road"