There was some natural avalanche activity on the peak south of mt Bole. Photo: Anonymous
We triggered a 12" soft wind slab on a NE facing slope at 9,5k'. Photo: J Gerardi
From email: "Rode buck today. It was very windy this week. Open areas are quite scoured, but there are still great stashes to be found if you hunt around. We triggered a 12" soft wind slab on a NE facing slope at 9,5k'."
We got into the Maid basin around 9:30 am while things were still cold. Much evidence of the recent wind event in the alpine with widespread wind slabs ranging in thickness from an inch to feet. There was some natural avalanche activity on the peak south of mt Bole.
Got an ECTN 19 and 23 on a SE aspect at 9300’ HS 95cm
This was on a thin layer of facets sitting under a crust at 58cm. With a few prior hand pits showing planar shear on this layer we opted to keep it low angle.
By noon things were getting quite warm and Skiing through the thinly covered, glopy bushwhack back to the trail was our crux for the day.
Snow rangers went as far as 3rd Yellowmule. We saw no new snow but evidence of wind effect, including a sizable, probable windslab avalanche Top of Macattee Basin
<p><span><span><span><span><span><span>Large </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>have been breaking on weak layers in the middle of the snowpack and near the ground (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=zCdhitUHk1o"><span><span><span><strong>…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/24/large-persistent-slab-avalanche-h… photo</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/24/persistent-slab-avalanche-fisher"… photo</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). If you get onto a steep slope today, expect to trigger a similar slide. These slides can be triggered from below, so be cautious passing beneath steep slopes as well.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The first big loading event of the season only ended 48 hours ago. Persistent weak layers are widespread - these weak layers (surface hoar and facets) often remain easily triggered for a couple days after a loading event ends and we expect that to be true 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. Choose slopes sheltered from the wind, less than 30 degrees steep, without steeper slopes above, for good, safe riding today.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Across the rest of our advisory area, triggering, large, dangerous avalanches is still possible, but they have become a bit less likely. The bulk of the last snowfall event had wrapped up by Monday night. High winds on Wednesday drifted lots of snow (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=w-aXzlPHrYA"><span><span><span><span><s… video</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>), but the snowpack has now had a few days break from loading.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Persistent Slab avalanches </span></span></strong></span></span></span><span><span><span><span><span><span>remain a serious concern. Weak layers are widespread in the middle of the snowpack and earlier this week we saw avalanches breaking on them. On Tuesday, I triggered a slide from 200 ft away on Buck Ridge (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32497"><span><span><span><strong><span…;). On Wednesday, an avalanche on Saddle Peak broke 1-3 feet deep, and ran 1500 vertical feet (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32548"><span><span><span><strong><span…;). A large collapse yesterday in the Bridger’s reminds us that similar slides remain possible (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/32582"><span><span><span><strong><span…;).</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Minimize potential consequences by choosing smaller slopes with clean runouts if you decide to get into steeper terrain today. Stay alert for signs of instability (cracking, collapsing, or poor test results). </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE.</span></span></span></span></span></span></p>
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar
I saw a wide slab avalanche up on west Woody Ridge from town. It happened late on Wednesday or overnight during or after the strong winds and snowfall. Photo: GNFAC
Wind slab avalanche near Lulu Pass. Photo: GNFAC
