Today we observed wet loose avalanches in steep, rocky terrain on the west side of Miller ridge. SW facing, 9500 ft
Toured much of the Hyalite zone yesterday. Winds calmed, sun came out mid day. 1” of new snow and 3” the day before. Skiing was great. Saw a couple huge cornices that had broken off. From the top of Devide peak we observed what looked like a cornice release above the headwaters of storm castle creek which triggered a slab, east facing aspect. Looked to be several feet deep and ran a long way. No other signs of instability observed. Great skiing. Solar aspects were saturated by the afternoon.
Ridge line just west of divide peak in Hyalite canyon. Photo: O Silitch
Saw a fairly fresh avalanche up Hyalite from the top of the Fat and Skinny Maids, I think that would put the avalanche in the Storm Castle Creek basin. Photo: F Miller
Ridge line just west of divide peak in Hyalite canyon
Saw a fairly fresh avalanche up Hyalite from the top of the Fat and Skinny Maids, I think that would put the avalanche in the Storm Castle Creek basin. North facing shady aspects were still cool and chalky, solar aspects were getting quite warm.
Got an early-ish start to beat the heat and was on top of Elephant Mountain by 9am this morning. Skied the southeast bowl for our first lap, which was supportable and mostly good corn skiing. It was unclear when solar aspects were going to fall apart, but I wouldn't have wanted to be skiing that bowl much later than we had. Very light wind, few clouds, and strong sun made for pretty rapid warming. The north aspect held cold snow down to 7500 ft or so, though it is quite shaded. Shout out to the party behind us up top for allowing me to engage them in meaningful communication about not skiing on top of us. That dialogue was appreciated. Lots of ski tracks in high places, pretty fun to see.
Another day of warm temps and clear skies allowed us to cover a lot of ground in the Southern Madisons. We rode into the Taylor Fork, up to the weather station, to the top of Carrot Basin, through Sage Basin, up and over into Cabin Creek, and all the way up to the head of Red Canyon.
We spotted a few old avalanches. One in Cabin Creek that was triggered two days ago by snowmobilers on a N facing aspect. At the top of Carrot Basin, we saw a small avalanche (R1-D1) on a N aspect that likely broke yesterday on buried weak layers. We also spotted one cornice-fall triggered (R2-D2) avalanche that broke earlier this week in Sage Basin and then an older cornice fall triggered slab in Sunlight Basin.
Another day of warm temps and clear skies allowed us to cover a lot of ground in the Southern Madisons. We rode into the Taylor Fork, up to the weather station, to the top of Carrot Basin, through Sage Basin, up and over into Cabin Creek, and all the way up to the head of Red Canyon.
There were a handful of small wet-loose avalanches on solar aspects that we noted throughout the day. While northerly aspects stayed cold, solar aspects became wet a couple inches down.
<p><span><span><span><span><span><span>Today, human-triggered </span></span></span></span></span></span><span><span><span><strong><span><span>persistent slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> can break on weak layers that formed in late January. Recent avalanches of this type have generally been 2-3 feet deep and 50-200’ wide, and two days ago near Lionhead we saw one that broke 5 feet deep on a heavily wind-loaded slope (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34421"><span><span><span><span><span><…;, </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=TWCNOrvNvLk&embeds_referring_euri=h…;). This was the latest in a string of persistent slab avalanches that were triggered over the last twelve days. Many of these were close calls with riders narrowly avoiding being caught and some partially buried and dug out by partners. (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34413"><span><span><span><span><span><… in Cabin Creek</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34368"><span><span><span><span><span><… in Cooke</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34341"><span><span><span><span><span><… in Tepee Basin</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34367"><span><span><span><span><span><… in Cooke</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34301"><span><span><span><span><span><… in Tepee Basin</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34327"><span><span><span><span><span><… in Taylor Fork</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=tAiSHSEDJhY"><span><span><span><span><s… last Wednesday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Yesterday we rode in the southern Madison Range and saw one recent small persistent slab, multiple cornice triggered large avalanches, and a few wet slides (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34438"><span><span><span><span><span><…;). In our snowpits we saw poor snowpack structure, and the recent string of human-triggered avalanches are clear signs that weak layers can still produce large avalanches.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>In our </span></span></span></span></span></span><a href="https://youtu.be/W_BeKTJQbUc?feature=shared"><span><span><span><span><s… from yesterday</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span> GNFAC intern Haylee describes the persistent slab problem and what to do about it: Your best options are either avoid slopes steeper than 30 degrees, or before committing to steep slopes dig down to check for a poor snowpack structure, and choose slopes with minimal consequences like gullies, trees or cliffs. Keep in mind many (not all) recent slides have been on mid-elevation slopes, surrounded by trees and sheltered from the wind.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Also watch out for triggering </span></span></span></span></span></span><span><span><span><strong><span><span>wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> on sunny slopes as the snow surface melts.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE around West Yellowstone and Cooke City.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>This morning avalanche conditions are generally safe and slides are unlikely. Danger will rise through the day for wet snow avalanches as above freezing temperatures melt the snow surface. Temperatures are already above freezing in many places this morning. Clear skies overnight probably helped the surface freeze at least a little, but that may change quickly with the warm temperatures and sunshine. </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>As the snow surface starts to melt, </span></span></span></span></span></span><span><span><span><strong><span><span>wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> will become a concern (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/25/wet-loose-pioneer-mountain"><span…;) and </span></span></span></span></span></span><span><span><span><strong><span><span>cornice falls</span></span></strong></span></span></span><span><span><span><span><span><span> could break off ridgelines. If you find more than a couple inches of wet snow at the surface seek lower angle or shadier slopes. Avoid spending time on slopes below cornices and give them a wide berth while traveling along ridgelines. Yesterday skiers in Hyalite noted cornices peeling off the ridgeline and a cornice fall that triggered a wind slab avalanche on the slope below (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34440"><span><span><span><span><span><…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is LOW this morning and will rise to MODERATE as the day heats up.</span></span></span></span></span></span></p>
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