Wet Slab in Yellowstone
Saw what looked like a wet slab avalanche from the road along the Madison River. Roughly north facing slope at 7500'.
Saw what looked like a wet slab avalanche from the road along the Madison River. Roughly north facing slope at 7500'.
On sunday 4/14 a large wet loose avalanche ran naturally in closed terrain at Bridger. The larger of the two in the photo, on the right, is from 4/14 at 1230pm. The other slide, on the left, happened yesterday or late in the day Friday.
On sunday 4/14 a large wet loose avalanche ran naturally in closed terrain at Bridger. The larger of the two in the photo, on the right, is from 4/14 at 1230pm. The other slide, on the left, happened yesterday (4/13) or late in the day Friday. Photo: BBSP
On sunday 4/14 a large wet loose avalanche ran naturally in closed terrain at Bridger. The larger of the two in the photo is from 4/14 at 1230pm. The other slide, on the left, happened yesterday or late in the day Friday.
Saw a slab avalanche on a NE face at around 9000-10000 feet. Did not see any signs of instability on the tour, but there was not a very concrete freeze. Everything below 8000 remained unfrozen.
<p><span><span><span><span><span><span>Temperatures remained above freezing for the third night in a row. Today will be another day of clear skies and above freezing temperatures which makes wet snow avalanches a likely hazard you will encounter on and below steep slopes. In the Bridger Range temperatures are what I would call “hot” with lows in the 40s F at all elevations this morning.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Loose wet avalanches ran naturally over the last few days. Today you can expect similar slides to run naturally and be easy to trigger on steep slopes (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31834"><span><span><span><strong><span… from Bridgers</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). The snowpack will continue to melt today, and without freezing overnight, slides have the potential to be larger with a possibility of bigger destructive wet slabs. In the Bridger Range the avalanche danger is CONSIDERABLE this morning, and it will quickly rise to HIGH. Travel in avalanche terrain is not recommended.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Where temperatures were closer to freezing, clear skies overnight probably helped freeze the snow surface at least a little. In some regards, the snowpack held up surprisingly well during the last few days of heat, but today could be the day it falls apart. Wet snow avalanches will quickly become a concern when the snow surface starts to melt with today’s sun and warm temperatures.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Stay diligent with careful snowpack assessment and cautious route finding. When the snow surface gets wet and unsupportable more than a few inches deep, wet avalanches will be possible and will quickly become more likely through the late morning and middle of the day. Plan to be off and out from underneath steep slopes before the snow becomes too wet, and make sure you have safe options for your egress out of the mountains.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Cornices along ridgelines have been weakening with the warm temperatures and breaking naturally, and a skier triggered one on the Sphinx on Thursday (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/24/cornice-collapse-sphinx"><span><s… photo</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). These can be dangerous on their own, and they can trigger larger slab avalanches (as this photo from </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/24/iceberg-peak-cornice-fall"><span>… Peak</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> demonstrates). A falling cornice could trigger an avalanche on the deeper weak layers we haven’t seen activity on in weeks. Give cornices a wide berth as you travel along ridgelines and minimize time spent on slopes below.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>On shady slopes where the snowpack has stayed dry you might still be able to trigger a wind slab or an avalanche on weak layers in the upper couple feet of the snowpack. Dig a quick snowpit and do a stability test to make sure you don’t get surprised.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE this morning and will quickly rise to CONSIDERABLE as the day heats up.</span></span></span></span></span></span></p>
Hyalite Road Closure: Hyalite road is closed to ALL MOTORIZED VEHICLES until the morning of May 16. This is a regular annual road closure to reduce road damage during the spring thaw. Bicycle and foot traffic are allowed. Contact the Bozeman FS Ranger District for more info.
Temps above freezing overnight, except Fisher Crk. and Lone Mtn. summit
This afternoon I drove up Bridger canyon to Seitz Rd to see the extent of wet snow activity, and stopped in a few places to look with binoculars. There were many loose wet avalanches that ran over the last 1-3 days. I estimate they involved the upper 6-12" of snow. Activity was widespread and many slides were plenty large enough to be dangerous, but there was nothing especially remarkable about the size and I saw zero wet slabs.
Temperature was 65-70 degrees in the canyon, mostly clear skies with a few clouds, calm to light wind.
On 4/13/24 There were many loose wet avalanches that ran over the last 1-3 days. They appeared to involved the upper 6-12" of the snowpack. Photo: GNFAC