Photo: R. Lindsey
Forecast link: GNFAC Avalanche Forecast for Mon Mar 27, 2023
Photo: R. Lindsey
A runner reported on 3/24/23: "I observed the results of a wet slide avalanche within the first mile of Middle Cottonwood Creek Trail. The slide came down from the south side of the canyon (north facing), and crossed the trail at about 4-5' deep and 10' across at the trail with debris and into the creek at the creek crossing about .75 mile from the trailhead. The crown was only about 100' up the side of the canyon. The avalanche would've occurred earlier in the week, there was just the skiff of snow on it from the previous light snow (22nd?)....
A runner reported on 3/24/23: "I observed the results of a wet slide avalanche within the first mile of Middle Cottonwood Creek Trail. The slide came down from the south side of the canyon (north facing), and crossed the trail at about 4-5' deep and 10' across at the trail with debris and into the creek at the creek crossing about .75 mile from the trailhead. The crown was only about 100' up the side of the canyon. The avalanche would've occurred earlier in the week, there was just the skiff of snow on it from the previous light snow (22nd?)....
Toured into Moser Creek on 3/25 to find some pow turns. Measured 85cm ~34” of new snow and saw many shooting cracks on a density change in the new snow but surprisingly no propagating pit test results. It seemed that the snow was so new and so low density that it wasn’t making a cohesive slab. There was a stark new to old snow interface.
As of this morning this fresh snow is forming a layer that just slips right off the sun-baked ice underneath. Respectfully recommend level 4 "high" avy danger for the Bridgers. Bridger Bowl didn't accurately report the snow received. There's significantly more than 7". It was crotch-to-waist deep on much of the mountain.
I observed the results of a wet slide avalanche within the first mile of Middle Cottonwood Creek Trail. The slide came down from the south side of the canyon (north facing), and crossed the trail at about 4-5' deep and 10' across at the trail with debris and into the creek at the creek crossing about .75 mile from the trailhead. The crown was only about 100' up the side of the canyon. The avalanche would've occurred earlier in the week, there was just the skiff of snow on it from the previous light snow (22nd?). In the rest of that section there are pinwheels all along that south canyon slope (north facing).
This is the 3rd wet slide I've seen in the last 3-4 weeks on Middle Cottonwood in the same region where the trail is on the south side of the creek (mile .4-.80 from summer trailhead). This area is easily accessible by hikers (I was running) and I've seen wet slides in that area 3 of the last 4 years once the sun hammers that south slope in the afternoon. I would expect more at the next warm spell after this current storm cycle.
<p><span><span><span><span><span><span>New snow, wind, and deeply buried weak layers make for dangerous avalanche conditions. Conditions are most dangerous in the places with the most new snow. The setup is right for some intense localized bursts of snowfall today - if it is snowing heavily, the danger is also spiking. Avalanches will be easily triggered anywhere the new snow has been wind drifted into deeper slabs and may also break in non-wind affected areas where snow totals are deeper. Watch for cracks shooting out in front of your skis or sled as a sign that the new snow is unstable and ready to avalanche on steep slopes.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The even more worrisome concern is that this new snow may tip the scales and cause huge avalanches to break deep in the snowpack (see </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=xMbg_YQfgmw&list=PLXu5151nmAvTi1DBS…’s video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> on Mt. Blackmore). The slide that broke 8-10 ft deep earlier this week on Elephant Mtn. (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28785"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>) is just the latest example of the huge avalanches that could be triggered or break naturally today. See the </span></span></span></span></span></span><a href="https://www.mtavalanche.com/avalanche-activity"><span><span><span><span… activity list</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> and our </span></span></span></span></span></span><a href="https://www.youtube.com/playlist?list=PLXu5151nmAvTi1DBS5B4DBCruL1ULhkt… videos</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> for many more examples of recent big slides. These avalanches have been breaking after even small loading events. When the skies clear after this storm I expect to see evidence of some big avalanches. Stay off of and out from under all steep slopes so you don’t trigger one and aren’t hit from above when a slide breaks naturally. Keep it simple - complete avoidance is the answer today.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Human triggered avalanches are likely and the avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>There is less new snow in Cooke City and less is expected today. Our concerns are the same as elsewhere, but new snow slides will be smaller and deep slabs are a little less likely. In no way does this mean conditions are safe. On Thursday, a slide near Daisy Pass broke 4 ft deep and 150 ft wide, catching two snowmobilers and breaking one of their femur’s (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28785"><span><span><span><strong><span… and photos</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.facebook.com/100004284780258/videos/1424658804963632?idorva…;). Similar slides are possible today. Avoiding steep slopes entirely is a reasonable strategy. If you are going to poke onto slopes steeper than 30 degrees choose smaller slopes with clean runouts (no trees or gullies beneath you) that haven’t been recently wind-loaded.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Large human triggered avalanches are possible and the avalanche danger is MODERATE. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</span></span></span></span></span></span></p>
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