Avalanche forecast

Avalanche forecast

Payette Avalanche Center
View on map

Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Triggering a 1-3' thick persistent slab avalanche is possible mostly on steep slopes facing North through East that are 35-45 degrees. Triggering a fresh, 1' thick wind slab is possible in leeward terrain as winds gusted into the 30mph range most of Saturday and skiers reported triggering a small wind slab north of McCall.

Use good travel protocols like 1 at a time on slopes steeper than 35 degrees and watching your partners from safe spots well out of the run-out of avalanche terrain.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2.5

    We have seen evidence from natural avalanches and human-triggered avalanches this week. Layers of surface hoar were buried just before the last 3 plus feet of snow that we have gotten since February 25th---A very stormy pattern with strong winds out of the SW and continued rounds of snow with it, and in between storms there were periods of clear skies where weak layers of surface hoar and graupel formed, now buried within the upper 2' of the snowpack. 

    Many steep slopes likely slid mid-storm over the last couple of weeks? Visibility was poor as snow and winds as well as dense clouds shrouded the peaks most of the time.  Triggering these layers is becoming difficult and is becoming less likely. 

    Riders on snowmachines are most likely to trigger these layers, especially in areas where the slab or the snow is shallow and rocky or near trees or other areas where the slab is thinner.

    Observations of this problem have been in wind and Sun sheltered terrain, with crowns just below the ridgeline mainly on East, Northeast, and North aspects. There is about 3-3.5' of snow in wind-loaded areas on this layer ( a thick, pencil-hard slab). Over the last 2 weeks, we have gotten a lot of good observations from riders and sliders from triggering avalanches and thankfully the outcomes were learning lessons from just a close call. 

    Extra caution is needed in terrain that is wind-loaded and sheltered, especially slopes 35-45 degrees where the slab can hang on above these weak layers. Avoid this type of terrain, yet if you do travel in or around it stack the odds in your favor and only expose 1 person at a time in your group while you watch from a safe spot well away from where the avalanche could run out to.

     

    (3/9/2024)

    The Avalanche triggered by snowmobile on  3/7/24 HS-AM-R2-D2.5

    Photo: George Halcom

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Winds gusted yesterday to around 30mph out of the SW and were sending plumes of snow into leeward terrain, Mostly North and East aspects. There was just enough snow available for transport to form fresh slabs about a foot thick that were sensitive yet small. We received a report of a skier triggering a small relatively harmless, D-1 wind slab yesterday unintentionally.

    Look for signs of loading as different terrain may load different aspects. Extreme terrain or consequential terrain like exposure or terrain traps are going to amplify the consequences of this small and fresh wind slab problem. 

    (3/9/2024) Public Observation near Fisher Cr Saddle:Debris from d1 wind slab avalanche

Avalanche Discussion

While the odds of triggering these persistent weak layers are less they are not going away this week. Human-triggered avalanches have been reported by both riders and sliders all week. The game or the message remains the same, use extra caution, and don't put your group in the runout, or in avalanche terrain together at the same time.  Group up far away from steep slopes. Keep the odds in your favor by doing simple things like digging a pit, wearing a transceiver with fresh batteries, 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.  

Wet snow and small amounts of rain may create small wet loose, mainly D-1 harmless avalanches in the upper snowpack between 5&6,000 feet. Temps are forecasted to trend warmer and warmer through the week with the valley seeing a mix of rain and snow, use caution in steep lower elevation terrrain.

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 Mile High Powersports on Highway 55 south of McCall.