21-22

GNFAC Avalanche Forecast for Mon Apr 4, 2022

Snowpack and Avalanche Discussion

<p>Large avalanches are unlikely today. The main avalanche hazard is slabs of wind-drifted snow that can break under the weight of a person and slide on steep slopes. These slabs will probably be small, but can be hazardous in high consequence terrain. Yesterday on Wilson Peak near Big Sky, two skiers triggered a small avalanche while they were ascending a slope. The slide caught one of the skiers who was pushed into a tree and injured (<a href="https://www.mtavalanche.com/node/26424"><strong><u>details and photos</u></strong></a>). The avalanche involved a slab of wind-drifted snow, 6-12” deep and 100 feet wide. Similar avalanches of recently wind-drifted snow were reported the last couple days by skiers in Beehive Basin (<a href="https://www.mtavalanche.com/node/26412"><strong><u>details</u></strong>…;), Cooke City (<a href="https://www.mtavalanche.com/node/26429"><strong><u>photo and details</u></strong></a>) and outside the advisory area in the Absaroka Range (<a href="https://www.mtavalanche.com/node/26409"><strong><u>details</u></strong>…;, <a href="https://www.mtavalanche.com/node/26422"><strong><u>details</u></strong>…;).&nbsp;</p>

<p>If you ride or ski in steep terrain today, watch for signs of wind-drifted snow such as cracking around your feet or skis, round “whales” of snow near ridgelines and below cornices, or hard slabs that may feel hollow. Stay off steep slopes where you suspect unstable drifts, especially where even a small slide could push you into trees, over a cliff, or knock you down a long steep slope.</p>

<p>Larger avalanches on deeper weak layers are unlikely, but not impossible (<a href="https://www.youtube.com/watch?v=0w18Fxp-dmI"><strong><u>Flanders video</u></strong></a>). Before riding steep slopes, dig to double check that a poor or unstable snowpack structure does not exist. Stack the odds in your favor by only exposing one person at a time to avalanche terrain and always carrying proper rescue gear.&nbsp;</p>

<p>Today the avalanche danger is LOW. This afternoon and tonight, new snow and strong winds will cause danger to increase. Be prepared for changing conditions. If snowfall accumulates earlier than expected, fresh drifts will form and larger avalanches could become possible.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our website, email (mtavalanche@gmail.com), phone (406-587-6984), or Instagram (#gnfacobs).</p>

Skier triggered (?) small slab on The Fin

The Fin
Cooke City
Code
SS-AS-R1-D1.5-I
Elevation
9700
Aspect
NE
Latitude
45.00460
Longitude
-109.95800
Notes

From email 4/3/22: "I noticed [this dry slab] this morning from town. I saw tracks on it yesterday afternoon (when we arrived) but didn’t notice the slide with naked eye, also super flat light yesterday afternoon... Looks like it could’ve been skier triggered, but maybe not, as there aren’t any tracks going through the path, must’ve been the last skier if that were the case.The debris can be spotted almost to the bottom of the bowl, so quite lengthy." Photo: P. Whitmire

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
R size
1
D size
1.5
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From email 4/3/22: "I noticed [this dry slab] this morning from town. I saw tracks on it yesterday afternoon (when we arrived) but didn’t notice the slide with naked eye, also super flat light yesterday afternoon... Looks like it could’ve been skier triggered, but maybe not, as there aren’t any tracks going through the path, must’ve been the last skier if that were the case.The debris can be spotted almost to the bottom of the bowl, so quite lengthy." Photo: P. Whitmire

Cooke City, 2022-04-04