Bollettino valanghe

West Slopes South

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

Expect the avalanche danger to rise during the day and as you ascend in elevation. All this new storm snow will be a hazard unto itself and also stress deeper layers in the snowpack. Consider staying off of all large steep slopes.

Problemi valanghivi

  • Storm Slabs

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

    As the new snow piles up, periods of heavy snowfall, fluctuating temperatures, and moderate winds could build potential weak layers. These may exist even on small open slopes and at any elevation. Look for cracking or tiny slabs on uptrack and small slope tests. Hand pits can also help you see strong over weak snow. Make sure to check all the way down to the 3/9 interface. 

    Prior to the storm, crusts, surface hoar, and facets were all reported in the zone. This could make it very easy to trigger one of these avalanches. Expect slides to be the largest and most dangerous in the afternoon and in wind-loaded areas.

    (1/22/2024)

    Example: A crack on a very small but steep slope highlights the unstable storm snow. 

    Photo: Dallas Glass

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    It’s really hard to say how this storm will affect the deeper layers in the snowpack. Will the new storm load on Sunday be enough to tip the scales? You certainly don’t want to be in an avalanche path and find out. 

    Facets near and just above the Early February Crust (EFC) produced numerous avalanches all across the zone during the past 10 days. The last observed avalanches were on Thursday. Snowpack tests predictably show sudden and propagating failures. Now, we’re adding more stress to these persistent layers. 

    You may not see any obvious signs that it’s dangerous. Tracks on a slope don’t mean it’s safe. The only tool we have to manage this unpredictable problem is to stay away from it. If you do travel in larger terrain, just recognize it’s a big gamble, and if you’re wrong, it’s probably going to be a huge avalanche.

    (3/7/2024)

    A very large (D3) avalanche on the Conrad Glacier below Gilbert Peak as seen from White Pass [N 7500']

    Photo: Andy Harrington

Avalanche Discussion

NWAC is devastated to report the death of one of our Avalanche Forecasters, Matt Primomo. Tragically, Matt passed away in a non-avalanche accident away from work on Thursday, March 7th. Matt has been a key member of the NWAC family since 2017. His life in the mountains touched so many people. We are absolutely heartbroken. Please join us as we mourn this immense loss with Matt’s family, friends, and community.

Discussion:

It will probably be pretty stormy to start the day as the main front pushes through the zone. With generally southerly winds, precipitation should favor Crystal Mt and Mt Rainier. Areas near White Pass and Mt Adams should see less snow. However, the winds will shift more southwesterly behind the front, which should precipitation to all parts of the zone. 

A few sun breaks later in the day could cause rollerballs and maybe a few small loose wet slides on steep sunny slopes. If things start to warm up, be prepared for these natural avalanches in steep, rocky terrain. 

The upper snowpack largely consist of well-settled right-side-up storm snow from late February. However, the Early February Crusts (EFC) and other mid-February layers (2/19, 2/14, 2/11) continue to linger. These layers are highly variable due to several sunny days and strong wind events. This left a nearly undiscernible pattern of weak snow over the EFC. If you dig, look for facets above the crusts about 3-6 ft below the surface. Unfortunately, given the variability, there’s no guarantee that your snow profile represents the nearby avalanche terrain. 

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