Avalanche forecast

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Avalanche danger

Thu
Alpine
1 · Low
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Sizable avalanches are unlikely, and most slopes are safe. Watch for isolated wind drifts at upper elevations. Very steep slopes that directly face the sun could produce small, natural loose snow avalanches (sluffs).

In the White Cloud Mtns, triggering a large avalanche on weak snow near the ground remains a possibility on very steep, rocky, wind-affected slopes. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    Early-season persistent weak layers (facets and depth hoar) in the lower snowpack are widespread throughout the Galena Summit & Eastern Mtns zone. Given the lack of snowfall in recent weeks, most slopes are now stable. But, triggering a large avalanche on these deeply buried layers could result in severe consequences.

    The White Cloud Mtns are the proverbial "elephant in the room"; the snowpack there (video to right) remains spooky enough that none of the SAC staff is willing to venture into very steep, rocky, alpine terrain. As you travel south into the Boulder and then the Pioneer Mountains, the slab thins because less snow has fallen (recent video from Pioneers here), decreasing both the expected size and likelihood of triggering avalanches.

    Throughout this zone, slopes where you are most likely to trigger large avalanches share the following characteristics:

    • Steep: Slopes in prime-time avalanche terrain around 35-45 degrees.
    • Wind-affected: Heavily wind-loaded by past or recent wind events.
    • Alpine flavor: Complex terrain with scree piles, rocky ribs, and cliff bands help to create thin snow cover where weak layers are closer to the surface.

    ADDITIONAL DISCUSSIONLast weekend's wind and snowfall formed small drifts and slabs at upper elevations. On Monday near Galena Summit, a skier intentionally triggered a small, recently formed wind slab. Today, similar drifts could remain sensitive to triggering where they formed above crusts associated with small faceted crystals. Watch for smooth pillows of stiffer snow, dunes, or wave-like patterns on the surface.

    On slopes that recently received more than a few inches of snow and directly face the sun, small, natural loose snow slides (sluffs) are possible today. This scenario will begin on E-SE aspects in the morning, shift to S-facing slopes during the day, and move over to SW-W aspects in the afternoon. If you're seeing small balls of snow rolling downslope, or if the snow surface is starting to feel moist and sticky, pay attention to what's above you. Sun-induced sluffs are most likely in very steep, rocky terrain sheltered from the wind. 

Avalanche Discussion

50 Shades of Green: Not All LOW’s are Created Equal

 You probably noticed today is the first day this season we assigned LOW danger to the entire forecast area.

  • Does that mean most slopes are stable? Yes.
  • Does that mean all slopes are bomber and incapable of producing avalanches? Heck no.

Here’s a quick rundown of specific areas we are seeing different shades of green, or LOW danger:

The White Cloud Mtns: This mountain range almost singlehandedly kept the Galena Summit & Eastern Mtns zone at MODERATE danger for another day or two. It hasn’t snowed much this month, but the snowpack structure at upper elevations remains ugly: a 3-4’ thick, hard slab perched above well-developed depth hoar crystals near the ground (see video).  During a SAC forecaster conference call last night, we unanimously agreed this is the one area we’re not yet interested in skiing or riding steep, rocky, upper elevation terrain. If we were hunting for the rogue avalanche large enough to bury people, this is where we’d go.

The central and southern Boulder Mtns and Pioneer Mtns: Danger-wise, these areas are the White Clouds’ little sibling. The snowpack structure is poor, but the combination of a lack of snowfall and extreme wind events has produced an abnormally thin snowpack. Also, it hasn’t snowed much at all this month. Triggering a large slab avalanche is unlikely, but it is not impossible. The odds of triggering a big slide generally decreases as you move from north to south. 

The eastern Smoky and northern Boulder Mtns (Galena Peak area): Below average snowfall all year has created a fairly weak snowpack that is now generally stable because it hasn’t snowed much in the past two weeks.

The Sawooth Mtns, western Smoky Mtns, and Banner Summit zone:  As usual, these areas have the deepest snowpack in our forecast area. The big January storm (30-50” of snow in 5 days) overloaded the depth hoar and facets near the ground, producing a widespread, deep slab avalanche cycle. Since that storm, this area has received well below average snowfall. The weak layers responsible for the January avalanche cycle look a lot better than they did in January; for now, they are hibernating, or dormant. Also, the weak layers are buried far enough below the surface (typically well over 3 feet) to significantly reduce the chances of people triggering large avalanches.   

The Wood River Valley Mtns south of Ketchum and the Soldier Mtns: This area has received less than 10” of snow this month, and the increasingly powerful sun angle is quickly decimating the snowpack on sunny aspects. Triggering a large avalanche in this area is very unlikely.   

The combination of sunny, spring-like weather and LOW avalanche danger means there’s a lot of fun to be had in the mountains. However, I’d encourage you to always consider the consequences of triggering even a small avalanche before pinning the throttle for that epic highmark or dropping into a committing line off a big peak. Where would the snow carry you if it released? If something “just doesn’t feel right,” there’s probably an underlying reason for your hesitation. While the alpine environment is beckoning, remember that triggering small avalanches is always possible in “extreme” terrain.  

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