Bollettino valanghe

Silver Valley & Bitterroot Mountains

Idaho Panhandle Avalanche Center
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Pericolo valanghe

Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The mountains of the Silver Valley have been the focus of yesterday's and last nights snowfall.  Temps in the 20s have kept the snowfall light and winds have been variable but mainly westerly so look for wind deposition to be your main concern today.  Faceting of the Lucky Friday crust is still a concern and northerly aspects with convex slopes should have your attention as likely places to encounter this problem.  Read on intrepid snowgoer.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Brian and Issy ventured out West of Wardner Peak from Silver Mountain yesterday and observed gusty west southwesterly winds most of the day and heavy snowfall that began later in the day.  The strong winds, new snow, and cold temps should have you keying in on where the heaviest wind deposition will be today.  I suspect that easterly aspects will be loaded but as winds shifted around last night you might find pockets of wind slab elsewhere.  Graupel was in the mix yesterday and this can form a touchy weak layer.  Graupel tends to collect in pockets below ridgelines and the combo of graupel under a windslab can be very touchy, but easy to find if you're looking.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    We observed faceted snow over and under the Lucky Friday crust at about 2 feet deep. This persistent weak layer is still showing signs of potential instability.  With last nights new snow and the additional weight, we have some concerns for the weak layer above the crust.  Now is the time to dive back in and see how it is reacting within your pit test.  Our biggest concern with the Lucky Friday crust is steep, open slopes on any aspect, but mainly northerly. Be extra cautious about convex slopes where the snowpack may be thinner and the weak layer over the crust weaker.  You'll know what you're looking at because there will be a pucker factor.  Think twice about getting out on these slopes because this is where our concern about the Lucky Friday crust is the greatest.

     

Avalanche Discussion

Yesterday we experienced  mild temperatures combined with new snow at and above treeline with some moderate winds.  The primary concern now is the good possibility of unstable windslab development at the upper and mid-elevations. Windslabs are likely to develop on north and northeast aspects. Windslabs can be tricky to identify at times so take time to assess the stability before committing to steep terrain. Issy Davis and Brian Hilland toured up to a location West of Wardner Peak.  Most of the day was partly cloudy weather. We experienced some rain down low in the valley floor but had great weather during our pit tests. It started dumping on the ski out and it made for some epic turns.  The pack is right side up down to the Lucky Friday crust meaning it is light on top and gaining density with depth, which is great. To our surprise we did make an interesting observation in our column test as we had a resistant planer fracture after moderate taps failing on a layer of very subtle facets located on the  top as well as within the melt freeze layers of the Lucky Friday crust.  We had no results on our extended column test. All this means we should all use caution on steeper terrain where consequences are higher.

Shout out to Ruthy from Silver Mountain for helping support the coordination for the forecast this week. Thanks Ruthy!

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