Bulletin d’avalanche

Bulletin d’avalanche

Payette Avalanche Center
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Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
Périmé — ce bulletin a expiré 2 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

It is possible to trigger a persistent slab avalanche 1-4' deep in sheltered terrain as well as a wind slab avalanche in leeward terrain.

We have had multiple reports of snowmobilers and skiers triggering avalanches. Southwest winds upwards of 40mph have been building slabs 1-2' thick with about 30" of new snow this week, mostly on SE, E, and North aspects.

Avalanche terrain is currently dangerous and requires avoidance or careful evaluation and travel protocols. loose dry snow avalanches are also possible in steep sheltered terrain.  Slopes steeper than 30 degrees should be treated with caution and the best travel protocols. Avoid wind-loaded terrain. Use extra caution near cornices and treewells that are growing more dangerous.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Dry clear periods of weather this last week formed layers of surface hoar that were easily triggered Monday and reported being triggered by skiers and snowmobilers Friday and Saturday. Saturday by a snowmobiler. Depth ranged from 1-3' deep

    Pinning down the exact location where this problem exists is going to be somewhat difficult, but you are most likely to trigger this persistent weak layer in areas where the Sun and wind have not been able to break it down: like mid-elevation wind and sun-sheltered terrain.

    Throughout the week we have been getting easy to hard propagating results on multiple layers of graupel and surface hoar which has been confirmed by observations from skiers and sledders.

    If you approach slopes steeper than 30 degrees that are sheltered, do so with caution and use good travel protocols like watching your partner from a great safe spot well out of avalanche terrain.

    (3/1/2024) skier triggered an avalanche from... a public observation on Granite Mtn ENE above Goose Lake.

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    Winds have gusted into the 40+ mph range out of the Southwest and done a good job of moving snow and forming slabs in mostly East through North aspects in the mountains as well as down to the valley floor for this week.

    Avoiding wind-loaded slopes is going to be your best bet today. Look for indicators of wind direction as some terrain has an effect on the wind, and may load a slope on a different aspect than what you may be expecting. If you are seeing cracking and or hearing or feeling collapsing, find another slope to travel on.

    (3/1/2024) Tamarack Resort-Wildwood bowl cornices growing from recent South winds Photo: George Halcom

  • Loose Dry

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    1–2

    Where the wind has not stripped off the snow and the slope is steeper than 38 degrees it is possible to get the upper snowpack moving with you. Use extra caution around terrain traps (like cliffs and gullies) that would expose you to being carried into bad places by loose dry snow.

     

Avalanche Discussion

Persistent weak layers are going to be a problem this week as Dangerous avalanche conditions are abundant...Great riding and sliding can still be found in terrain that is without consequence. Traveling in and around avalanche terrain is going to take skill and patience. Most aspects are going to be soft, so don't expose yourself or your group to more hazards than you need, and most importantly, stack every odd in your favor.

Giving Extra caution and distance near tree wells and cornices is a good idea as 30" of new snow this week and intense Southern winds have formed features in exposed and sheltered terrain, also loading up the trees with snow. 

The basic things like wearing a transceiver, checking your partners for transceiver function, Shovel and probes on your back, traveling one at a time through terrain steeper than 30 degrees, and watching your partners from a safe spot are going to be prudent to success in the mountains. 

Check out all of the great observations from sliders and riders who have reported triggering avalanches throughout the week. They will be entered in our monthly drawing for submitting an observation, and you can too!

Today's advisory is sponsored by Tamarack Resort.