18-19

A skier in the Northern Bridgers found variable conditions on Saturday, with wind scouring above treeline, isolated wind slabs below treeline, and widespread faceting with the recent cold and dry weather. "Skiing was highly variable, ranging from all loose facets to breakable wind slab overlying facets to hard slab/sastrugi." Photo: G. Antonioli

Bridger Range, 2018-12-08

GNFAC Avalanche Forecast for Sat Dec 8, 2018

Snowpack and Avalanche Discussion

<p>With the exception of the Lionhead area near West Yellowstone, the snowpack throughout our advisory area is 2-3 feet deep, supportive, and lacks widespread buried weak layers. We observed these generally stable conditions over the past week in Hyalite (<u><strong><a href="https://www.youtube.com/watch?v=450oUoQ6QYs&amp;index=2&amp;list=PLXu51…;), Taylor Fork (<strong><a href="https://www.youtube.com/watch?v=L8OXT0t4Eak&amp;index=5&amp;list=PLXu51…;), near Big Sky (<u><strong><a href="https://www.youtube.com/watch?v=450oUoQ6QYs&amp;index=3&amp;list=PLXu51…;), and the Bridger Range (<strong><a href="https://www.youtube.com/watch?v=yLfkYW66kDE&amp;index=6&amp;list=PLXu51…;). The snowpack near West Yellowstone is shallower and weaker (<strong><a href="https://www.youtube.com/watch?v=hl5lygIF7s4&amp;index=9&amp;list=PLXu51…;), but generally stable for now without recent snow and wind.</p>

<p>Reported avalanche activity last week was confined to small avalanches of new and wind-drifted snow (<strong><a href="https://www.mtavalanche.com/avalanche-activity">Avalanche Activity</a></strong>). Four days without snow or heavy wind-loading makes avalanches unlikely to be triggered today. Ice climbers in Hyalite&nbsp;triggered a small wind-drifted pocket of snow yesterday (<strong><a href="https://www.mtavalanche.com/images/18/ice-climber-triggered-small-wind-…;), which shows avalanches are not impossible. Remain cautious of wind-loaded slopes and assess the consequences of being caught in even a small slide. Today, generally safe avalanche conditions exist and the avalanche danger is rated <strong>LOW</strong>.</p>

<p>Check out the <strong><a href="https://www.mtavalanche.com/snowpits">snowpit profile page</a></strong> on our website for a snapshot of the snowpack structure across our advisory area.</p>

<p>If you get out and have any avalanche or snowpack observations to share, contact us via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u&gt;, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u&gt;), 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.

BOZEMAN

Tomorrow, December 9, Beacon Park for the Bozeman Ice Fest, Grotto Falls parking lot, Hyalite Canyon, 10 a.m. to 2 p.m.

Ice climber triggered small wind pocket Hyalite

Hyalite - main fork
Northern Gallatin
Code
SS-AFc-R1-D1-I
Aspect
NW
Latitude
45.43950
Longitude
-110.96200
Notes

From e-mail: "The wind picked up after noon today and we observed moderate amounts of blowing snow at and above tree line. My climbing partner and I were able to trigger a small loaded pocket between slot corner and curtains, 30 deg, NNW aspect, which failed 6 inches deep and 15 ft wide on diurnal facets (old snow surface). The slab didn't move much due to the stubborn angle..."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Foot penetration
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
1
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
6.0 inches
Slab Width
15.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

GNFAC Avalanche Forecast for Fri Dec 7, 2018

Snowpack and Avalanche Discussion

<p>The lack of new snow and wind has created generally stable conditions. Yesterday, Doug and I found good stability in the gullies around Hyalite (<strong><a href="https://www.youtube.com/watch?v=450oUoQ6QYs&amp;index=2&amp;list=PLXu51…;). Alex also found stable conditions on Buck Ridge south of Big Sky (<strong><a href="https://www.youtube.com/watch?v=450oUoQ6QYs&amp;index=3&amp;list=PLXu51…;). We did receive one report of a natural avalanche outside of Cooke City. This slide appeared to be the result of heavy wind loading earlier in the week (<strong><a href="https://www.mtavalanche.com/images/18/natural-avalanche-cooke-city-9">p…;).</p>

<p>Today, it’s unlikely that avalanches will be triggered on wind loaded slopes, but it’s not impossible. Watch for and assess areas of wind drifted snow before committing to steeper terrain. It only takes a small slide to create a dangerous situation, especially in a thin early season snowpack.</p>

<p>Outside of isolated instabilities the snowpack is generally stable. Check out our snowpit profile page&nbsp;for a complete list of profiles across the advisory area (<strong><a href="https://www.mtavalanche.com/snowpits">profile page</a></strong>). &nbsp;&nbsp;&nbsp;&nbsp;</p>

<p>Today, generally safe avalanche conditions exist and the avalanche danger is rated&nbsp;<strong>LOW</strong>.</p>

<p>Alex will issue the next advisory tomorrow morning by 7:30 a.m. If you get out and have any avalanche or snowpack observations to share, contact us via our <u><a href="https://www.mtavalanche.com/node/add/snow_observation">website</a></u&gt;, email (<u><a href="mailto:mtavalanche@gmail.com">mtavalanche@gmail.com</a></u&gt;), 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.

BOZEMAN

Today and December 9, Beacon Park for the Bozeman Ice Fest, Grotto Falls parking lot, Hyalite Canyon, 10 a.m. to 2 p.m.