18-19
GNFAC Avalanche Forecast for Fri Nov 23, 2018
Snowpack and Avalanche Discussion
<p>For those choosing to escape the Black Friday frenzy by heading into the hills, keep in mind both Bridger Bowl and Big Sky Ski Resorts are open. If you venture into the backcountry, carefully assess the new snow-old interface, especially on slopes loaded by west-southwest winds. Yesterday, the Big Sky Ski Patrol saw both natural and human triggered avalanches during control work. It only took a few inches of new snow combined with strong winds to create cohesive slabs that failed easily. A skier up Hyalite also observed a natural avalanche that likely occurred yesterday (<a href="https://www.mtavalanche.com/photos">photo</a>). </p>
<p>The culprit for such touchy conditions is a weak layer of near surface facets or surface hoar that formed during the recent spell of high pressure. On Wednesday, I found this layer in Hyalite and Doug and Alex also found it in Cooke City (<a href="https://www.youtube.com/watch?v=l0qvNwadm7Y&list=PLXu5151nmAvRNl9ku…;, <a href="https://www.youtube.com/watch?v=M8ocv28K8eU">video</a>, <a href="https://www.mtavalanche.com/photos">photo</a>). This weak layer is now capped and loaded by new and wind-blown snow. We lack snowpack data from the mountains around West Yellowstone, but we assume the snowpack is weak in that area as well. </p>
<p>As the avalanche danger continues to rise, now is not the time to push it in avalanche terrain. This means keeping slope angles lower than 35 degrees and avoiding lower angle slopes attached to steeper slopes above. In addition to conservative terrain management and careful snowpack assessment, it’s imperative that everyone carries proper rescue gear and knows how to use it. With more snow and wind on the way, expect dangerous avalanche conditions through the weekend. </p>
<p>New this season, we added hyperlinks to the <u><strong><a href="https://www.mtavalanche.com/weather/wx-avalanche-log">Weather and Avalanche Log</a></strong></u> and a new Menu item <<u><strong><a href="https://www.mtavalanche.com/avalanche-activity">Avalanches and SnowPits</a></strong></u>> with information on avalanche activity and incidents.</p>
<p>If you get outside send us an observation via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u>, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u>), phone (406-587-6984), or Instagram (#gnfacobs).</p>
Upcoming Avalanche Education and Events
Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar.
November 26, MSU Snow and Avalanche Workshop, 5-9pm at MSU SUB Ballroom A
Wind slab avalanches on Blackmore
Mt Blackmore
Northern Gallatin
Code
HS-N-R1-D1
Elevation
9500
Aspect
E
Latitude
45.44430
Longitude
-111.00000
Notes
From an email:
"Went up to Blackmore for a pre-Thanksgiving dinner walk yesterday. Winds had moved a good bit of snow since Wednesday and I observed debris from several avalanches on the east face...Most of the slides were thin, probably fresh wind slabs failing on the latest batch of NSFs. The largest slide had some pretty sizeable chunks of hard slab style debris in it."
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
1
D size
1
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
Wind is moving snow creating wind slabs on the east face of Blackmore up Hyalite. This avalanche was seen on Thanksgiving. More snow and wind will create more wind drifting and more avalanches. Photo: B. VandenBos
Avalanche Details: Wind slab avalanches on Blackmore
Forecast link: GNFAC Avalanche Forecast for Fri Nov 23, 2018GNFAC Avalanche Forecast for Sat Nov 24, 2018
Northern Gallatin, 2018-11-23
Forecast link: GNFAC Avalanche Forecast for Fri Nov 23, 2018GNFAC Avalanche Forecast for Sat Nov 24, 2018
Weather and Avalanche Log for Fri Nov 23, 2018
More snow and wind on the way.