22-23

small storm slab inbounds at Bridger

Date
Activity
Skiing

Small storm slab off the steep drift on skier's R/skinner's L side of upper Thunder Road. Also felt some cracking and collapsing when I (briefly) stepped off the skin track to get to the top of Pierre's Knob. 

Region
Bridger Range
Location (from list)
Bridger Bowl
Observer Name
Alexey

Bridger Bowl Touring

Date
Activity
Skiing

skinned up to the ridge and observed 5-9 inches of new and accumulating snow forming into wind drifts that were highly reactive. Multiple remote triggers occurred while traveling N on the ridge, propagating  both on W and E faces of the ridge. Both Hidden and Northwest Passage slid with little effort down to an icy bed surface. Debris at bottom of hidden was substantial but great skiing. 

Region
Bridger Range
Location (from list)
Bridger Peak

GNFAC Avalanche Forecast for Fri Apr 14, 2023

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>The new snow creates dangerous avalanche conditions and makes human-triggered avalanches likely, especially in areas that received more snow and where moderate winds drifted snow into thicker slabs. Yesterday’s snow fell on a firm crust on many slopes which will make avalanches slide easier and break wide, even where snow is not drifted into denser slabs. Over the next couple days warm temperatures and sunshine will make the new snow unstable as it gets wet. This weekend, avalanches within the new snow will remain possible whether dry or wet, and the chances for large wet snow avalanches will increase the more the snow surface gets wet later in the weekend.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>This time of year stability can change drastically over the course of the day, or from one slope to another. Carefully assess the stability of the new snow throughout the day and as your terrain choices change with regards to exposure to sunshine, wind, and temperature (different aspects and elevations). When the sun is shining or temperatures are above freezing, expect avalanches to become more likely later in the day, especially on slopes that receive direct sun. This weekend plan to be off and out from below steep slopes before the snow gets wet and weak. If you are sinking above your ankle in wet snow, or see natural rollerballs or avalanches it is past the time to seek lower angle or shadier slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Weak layers buried 2-3 feet deep and near the bottom of the snowpack are not to be forgotten. Avalanches on these layers are becoming less likely, but the consequences remain potentially deadly or very destructive. On high, shady slopes it could still be possible to trigger a dry deep slab on these layers. Large wet slab avalanches might break on these layers when the recent snow gets melted and drains weakening water into the snowpack. Your best bet to avoid these is to choose simple, low angle terrain, especially during and after storms or on sunny, hot days.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>As temperatures warm this weekend, give cornices a wide berth along ridgelines and avoid slopes directly below them. Last week there were large cornice breaks on </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/cornice-fall-mount-abundance"><sp…. Abundance</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, and in </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/giant-cornice-collapse-north-madi… Madison</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Recent deep slabs (4/2-4/6): </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29012"><span><span><span><strong><span… Madison Range</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29004"><span><span><span><strong><span… Gallatin Range</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28949"><span><span><span><strong><span… Area</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> and </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/28900"><span><span><span><strong><span… Range</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Wet avalanches last weekend (4/8-4/11): </span></span></span></span></span></span><a href="http://www.mtavalanche.com/node/29091"><span><span><span><strong><span>… at Bridger</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29074"><span><span><span><strong><span… on Baldy</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29078"><span><span><span><strong><span… Peak</span></span></u></span></strong></span></span></span><span><span><span><span><span><u><span><span> </span></span></u></span></span></span></span></span><span><span><span><strong><span><u><span><span>and</span></span></u></span></strong></span></span></span><span><span><span><span><span><u><span><span> </span></span></u></span></span></span></span></span><span><span><span><strong><span><u><span><span>Bridger</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29080"><span><span><span><strong><span… Sky</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29071"><span><span><span><strong><span… road in YNP</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29022"><span><span><span><strong><span… Lake over Hwy</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Our </span></span></span></span></span></span><a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><span><span><span… and weather log</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> shows avalanche activity occurred on most days for the past few months, and avalanches are not stopping quite yet.&nbsp;</span></span></span></span></span></span><span><span><span><span><span><span>We will issue spring snowpack and weather updates twice a week through April, and we will share relevant avalanche and snowpack information on our website and social media. 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).</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Island Park got 10” of new snow which creates dangerous avalanche conditions and makes human-triggered avalanches likely. This weekend avalanches within the new snow will remain possible whether dry or wet, and the chances for large wet snow avalanches will increase the more the snow surface gets wet later in the weekend.</span></span></span></span></span></span></p>

Info and Reminders

Bridger Bowl Ski Area is closed, and ski patrol is no longer performing rescues and making terrain closure decisions for you (video).

Huge Wet Slide Centennials

Date

Photo from IG 4/13/23: @waxeman

Region
Island Park
Location (from list)
CENTENNIAL RANGE
Observer Name
@waxeman

Natural wet slide, Close Call/slushman ravine

Bridger Bowl
Bridger Range
Code
WL-N-R3-D2-O
Elevation
8000
Aspect
SE
Latitude
45.81560
Longitude
-110.92300
Notes

a natural wet slide came out of Close Call yesterday afternoon (4/11/23), debris ran to the bottom of moonshine.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Natural trigger
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Wet Snow
Slab Thickness
14.0 inches
Vertical Fall
600ft
Slab Width
30.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year