Lawinenlagebericht

Selkirk Mountains

Idaho Panhandle Avalanche Center
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Lawinengefahr

Mon
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Kernpunkte

The rollercoaster of wild weather, challenging access conditions, and wide range in snow depths across the same forecast zones all contribute to a higher degree of uncertainty than normal. What we do know is that new snow and elevated winds continue to work in unison and build fresh slabs on leeward-facing slopes. The best way to manage a highly variable snowpack equation is to diligently monitor conditions in front of you and be willing to adapt travel plans as the solution may or may not become clear. Put more weight on free, non-biased evidence of unstable snow like cracking, collapsing, and recent avalanche activity versus trying to guess at the problem's solution.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Snowfall Saturday and overnight delivered varying snow totals from south to north in the Selkirk Mountains. The southern end received a trace to an inch, while the northern portions of the zone received around eight inches of new snow. Winds have also been steadily pegged in the 20s mph out of the west-southwest - the prime snow transport window. This is likely thickening drifted slabs on northerly and easterly-facing slopes at mid and upper elevations with about 6 inches of new snow or more, and increasing their sensitivity.

    These slabs sit above the most recent rain crust that got deposited overnight Thursday when the rain line spiked over 6,000 feet. We don’t know the upper extent of the most recent rain line since we have struggled to access higher elevations from abundant downed trees and other hurdles accessing the continuous snow line. A common theme we’ve observed this season is that shortly after new snow falls on a very moist crust or saturated snowpack, the snow quickly facets. 

    The degree of faceting, and depth and hardness of the slab above will greatly influence your chance to trigger an avalanche. Look for and steer clear of lens-shaped pillows and remember that even a small slide could lead to a bad outcome because of many shallowly buried natural obstacles to get pushed into or over.

Avalanche Discussion

Nailing down conditions is a challenge at present. This is a function from frequent oscillations between snow and rain, varying amounts of each precipitation flavor, and broad elevation extent of snow cover. Throw in other non-snow logistical challenges like many downed trees, washed out road access, and frankly…no snow to travel the long distances necessary to access the plentiful snowpack and this leaves lots of assumptive thoughts on the table. All of this makes it hard to call a spade a spade.

Field teams over the past two days had high hopes of accessing the mountains to assess the upper extent of Thursday night’s rain and look for soft snow conditions, and evaluate upper snowpack layering. These dreams were quickly dampened by the presence of a robust rain crust from rain exceeding 6,000 feet…again…or not making it to the starting spot due to other access factors out of their control.

Thankfully, snowfall continues in the mountains and the snow line forecast looks slightly more promising than it has been. Although, we will believe it when we see it and really need the snow line to drop lower in elevation to help the cause.

If you are motivated to navigate conditions at lower elevations and reach the continuous snow line, avalanche concerns will likely be confined to wind-drifted slabs sitting above the upper most rain crust. Prior, older crusts exist in the top two to three feet of the snowpack and our limited field observations have noted them breaking down and faceting. We still think bigger snow loads are needed for deeper failures, but if you push above the most recent rain line, the scenario and end consequence is likely different. Places that avoided Thursday’s rain will harbor thicker and more cohesive slabs of snow sitting above…another crust…that have potential to produce a larger, more dangerous slide. The unfortunate part is we don’t know exactly what that elevation is and it likely varies between our forecast zones.

Digging down as you travel around the mountains - especially at higher elevations - is the only way to paint a better picture of what’s below your feet. If you encounter noticeable snow surface hardness changes or see phat, lens-shaped pillowy areas, pivot your travels to lower-angled slopes or ones without steeper overhead hazards. And while you’re at it, burn a pair of old skis to help out the meager snow conditions.

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