20-21

GNFAC Avalanche Forecast for Fri Apr 30, 2021

Snowpack and Avalanche Discussion

<p>Large wet slab avalanches are likely today and tomorrow. Temperatures are the warmest that this winter’s snowpack has felt, reaching 40s and 50s F the last few days and not dropping below freezing the last two nights. We received a report from someone who traversed the Bridger Range on Wednesday and saw multiple wet slides, some that broke a couple feet deep (<strong><a href="https://www.mtavalanche.com/node/24881">photos and details</a></strong>). As temperatures reach 60s F today, large wet snow avalanches will occur naturally, and will be easy to trigger if you travel on steep, snow-covered slopes. On Saturday afternoon, any steady rain in the mountains could trigger wet snow avalanches. Wet slides could remain possible to trigger on Sunday if the snowpack does not freeze Saturday night.</p>

<p>The weak, unconsolidated snowpack creates poor skiing and riding conditions and difficult travel. Don’t fight it, winter will return on Sunday. During these summer-like days while the deep, recently dry snowpack melts, consider off-snow activities or limit travel to low angle slopes. Get the bike out, maybe hit the river or crag. Regardless of your activity, minimize time spent underneath steep, snowy slopes even if the ground under your feet is dry.</p>

<p>Sunday and next week, conditions will be more appropriate for skis or a snowmobile. The snowpack will freeze most nights and avalanche concerns will involve new snow that falls, or small wet slides as the snow surface melts through each day. Avalanches will continue until the snowpack has melted. Remain diligent with careful snowpack assessment and cautious terrain selection. See below for additional general spring snowpack and travel advice.</p>

<p>Continue to share your avalanche observations. We will post them on our website/media to help each other stay safe. Thank you for your support and see you next fall. You can submit observations 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>

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Natural wet slides in Bridger Range, 4/26-4/28

BRIDGER RANGE
Bridger Range
Code
WL-N
Latitude
45.85120
Longitude
-110.94800
Notes

From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". 

Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Natural trigger
Problem Type
Wet Snow
Images
Wet slides in Bridgers 2
Wet slides in bridger range
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
20-21

From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". Photo: J. Harrison

Avalanche Details: Natural wet slides in Bridger Range, 4/26-4/28
Forecast link: GNFAC Avalanche Forecast for Fri Apr 30, 2021
Bridger Range, 2021-04-30
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    • From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". Photo: J. Harrison

    Avalanche Details: Natural wet slides in Bridger Range, 4/26-4/28
    Forecast link: GNFAC Avalanche Forecast for Fri Apr 30, 2021GNFAC Avalanche Forecast for Mon May 3, 2021
    Bridger Range, 2021-04-30
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    • Natural wet loose slides in Absarokas

    Livingston
    Out of Advisory Area
    Code
    WL-N-R2-D2
    Elevation
    9000
    Aspect Range
    NW, W, S
    Latitude
    45.42600
    Longitude
    -110.49500
    Notes

    From obs 4/28/21: "Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point."

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Wet loose-snow avalanche
    Trigger
    Natural trigger
    R size
    2
    D size
    2
    Problem Type
    Wet Snow
    Images
    Natural wet loose slides in Absarokas
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    20-21

    From obs 4/28/21: "Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point." Photo: T. Benson

    Avalanche Details: Natural wet loose slides in Absarokas
    Out of Advisory Area, 2021-04-29
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    • Absaroka, greater Mill Creek region between 8500’ and 9500’...

    Date
    Activity
    Skiing

    Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point. Nothing crazy just thought I’d pass along.

    Region
    Out of Advisory Area
    Location (from list)
    Livingston
    Observer Name
    Natural, wet, loose in the Absarokas

    Ross Peak/ Banana Couloir

    Date
    Activity
    Skiing

    This morning we toured up Ross Peak to check out the effects of the heat and sun these past few days. On our ascent, we observed the potential for wet slabs on an eastern aspect through a series of hand shear tests (photo). The top most layer displayed a Q1 shear quality with medium effort. To the north, we observed a natural wet slab on a southern aspect (photo). Runnels were widespread in the area, and observed on southern to northeastern aspects (photo). We found a breakable sun crust above the recent snow on eastern and north eastern aspects. In the Banana, we observed debris from wet loose releases off the cliff face that travelled far down the southern face (photo). We were travelling in this area before temperatures climbed too high, but signs of instability are becoming more obvious on all aspects. Driving along the Bridger Range, wet loose slides and smaller wet slabs were widespread by the afternoon.

    Region
    Bridger Range
    Location (from list)
    Ross Peak
    Observer Name
    Erich Schreier
    Subscribe to 20-21