Avalanche forecast

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

Triggering an avalanche on weak snow near the ground remains a possibility on very steep, rocky, wind-affected slopes. You'll be most likely to encounter this problem at upper elevations in the White Cloud and Boulder Mountains. Increasing wind speeds today may build isolated but touchy slabs in upper elevation terrain. At mid and lower elevations, or on more wind-sheltered slopes, the snowpack is generally stable.

Avalanche problems

  • Persistent Slabs

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

    The remnants of early-season snowfall make up the base of the snowpack in much of this zone. In the White Cloud Mountains, which received the most snow during December and January, this base is supporting a meaty 3-4' thick slab of snow (video at right). As you travel south into the Boulder and then the Pioneer Mountains, the slab thins because less snow has fallen. Thanks to a lack of recent loading, triggering a large avalanche involving this weak snow has become unlikely, but I'd recommend continuing to factor it into your decision-making in terrain with 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 DISCUSSIONIncreasing wind speeds today may pick up the faceted snow that formed on the snow surface this week and build isolated slabs in exposed, upper elevation terrain. While small, encountering one of these slabs in very steep and rocky terrain could have high consequences. These slabs will increase in distribution and size as the wind blows.

Avalanche Discussion

The weather pattern for our neck of the woods has been fairly stable for the month of February. A stubborn ridge of high pressure docked along the west coast has forced moisture to our north and kept things high and dry here in central Idaho. But even though the weather has stagnated, the snowpack never sleeps. Solid materials (snow) near their melting point are in a constant state of change. If you've been out this week for a few days in a row you've probably noticed some of these changes. Maybe the skiing actually improved in your favorite powder stash as the snow surface weakened and faceted. These facets can make for some good riding conditions ("recycled powder"), but they also make for reactive weak layers.

Today, a short-lived flattening of the ridge will allow for a little moisture to squeak into central Idaho. Ahead of this moisture, we should see an uptick in wind speeds for the first time since last weekend's storm. In our northern forecast zones, a good bit of unconsolidated snow (the remnants from that storm) can be found, particularly on shaded slopes. Our southern areas received very little snowfall during this storm, but the snow has faceted significantly, leaving a layer of weak snow resting on the surface. Across our forecast zones, today's increasing wind speeds will be picking up whatever loose snow it can find and transporting it. Near features that slow the wind down and force it to drop the load that it is carrying, such as ridgelines and mid-slope features like ribs and gullies, fresh slabs will build. These slabs will be much thicker and touchier in our northern areas because there is more snow available for transport, but even down south we may see some isolated wind slabs building. Across the region, these slabs will be deposited on the weak snow surface that formed this week.  

Regions covered