20-21

GNFAC Avalanche Forecast for Sun Mar 7, 2021

Snowpack and Avalanche Discussion

<p>In the Bridgers, 4” inches of new snow equal to 0.5” of snow water equivalent (SWE) and moderate southwest wind formed fresh drifts along ridgelines. If you see these drifts crack under your skis, it is a sign they are unstable and steeper wind-loaded slopes should be avoided. This afternoon, sunshine and above freezing temperatures could make the new snow moist and make it possible to trigger wet loose avalanches. These slides can appear small, but are powerful and potentially deadly if they catch you in high consequence terrain. Additionally, a small slide or a human can trigger large to very large avalanches on weak snow near the ground. These deep slabs are becoming more difficult to trigger, but new snow today keeps it possible. Avoid travel on and underneath steep, sunny slopes this afternoon, and carefully evaluate stability of new snow and fresh drifts. Today avalanche danger is MODERATE.</p>

<p>In the mountains south of Bozeman to West Yellowstone weak snow near the ground creates an unstable structure, and skiers or riders can trigger large to very large deep slab avalanches. I skied in Beehive Basin yesterday and found the faceted snow near the ground is still very soft and weak (<strong><a href="https://www.youtube.com/watch?v=SKsouRY6fhg&amp;list=PLXu5151nmAvQDzKmH…;). A skier near Maid of the Mist in Hyalite saw deep avalanche crowns (<strong><a href="https://www.mtavalanche.com/images/21/deep-slab-avalanche-near-maid-mis…;, <strong><a href="https://www.mtavalanche.com/images/21/deep-slab-near-arden-peak">photo<…;), and we received a <strong><a href="https://www.mtavalanche.com/images/21/deep-slab-s-madison-ennis">photo of a huge slide in the southern Madisons</a></strong>. These broke in the last week or two and remind us what is possible. Deep slabs are getting more difficult to trigger each day without snow or wind-loading, but the potential large consequences require conservative travel choices and diligent snowpack assessment.&nbsp;Today there is a lingering possibility to trigger a deep slab avalanche and avalanche danger is MODERATE.</p>

<p>On slopes that receive direct sun, surface crusts will be slow to melt due to clouds this morning and cooler temperatures than recent days, and wet snow avalanches are unlikely. Remain cautious of steep, sunny slopes this afternoon if the snow surface becomes wet.</p>

<p>In the mountains near Cooke City the snowpack lacks widespread buried weak layers and avalanches are unlikely. Be cautious of small wet loose avalanches later in the day on slopes that receive direct sun. Before riding steep slopes, assess the snowpack for buried weak layers. A couple recent natural avalanches west of Cooke City, outside our advisory area, should keep us on our toes and show the type of slopes where unstable weak layers may exist (<a href="https://www.mtavalanche.com/node/24530"><strong>photo and details</strong></a>, <strong><a href="https://www.mtavalanche.com/images/21/bison-tracks-and-avalanche-ynp">p…;). The avalanche danger is LOW in the mountains near Cooke City.</p>

<p>If you get out, please send us your observations no matter how brief. You can submit them via our <a href="https://www.mtavalanche.com/node/add/snow_observation"><strong>website<…;, email (<a href="mailto:mtavalanche@gmail.com"><strong>mtavalanche@gmail.com</strong></a…;), phone (406-587-6984), or Instagram (#gnfacobs).</p>

The Beacon Park at Beall Park in Bozeman is running!

The Friends of the Avalanche Center in partnership with the City of Bozeman put in a Beacon Park at Beall Park. It is located on the north side of the Beall building between N. Bozeman Ave. and the ice rink.

Natural avalanche (bison trigger?) in YNP near Cooke

Out of Advisory Area
Code
Notes

 

From obs: 3/6/21: "Observed several smallish avalanches in Yellowstone National Park today. The interesting thing about this one is the bison track that goes into the slide . No telling if the avalanche was triggered by the bison, but the shallow snowpack is about 1/2 faceted, so maybe it was remotely triggered. Resulting in a grizzly springtime snack??"

Number of slides
1
Number caught
0
Number buried
0
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year