Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

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

In sintesi

An incoming storm is increasing avalanche danger throughout the day, so danger may start lower, but you can expect human-triggered avalanches to be likely as the day progresses. In locations with deep enough deposits of newly fallen storm snow there's a chance you could trigger a slab avalanche, although wind-drifted areas will be more reactive and produce larger avalanches. Avoid slopes greater than 35 degrees where over 6 inches of new storm snow is present, especially if you're identifying red flags like recent avalanches or long shooting cracks running from your feet or sled. 

Problemi valanghivi

  • Storm Slabs

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

    The day may start with Moderate avalanche danger, but you can expect the danger to increase to Considerable around midday. By the end of the day, storm totals are expected to reach around an inch of water, which will probably equate to about a foot of snow. In non wind-affected areas, storm slabs are likely to avalanche with a human trigger. During the first half of the storm, temperatures are forecasted to increase, meaning we could see a bit of an "upside down" snowpack, leading to more touchy avalanche conditions. Thankfully temperatures will cool as the storm progresses, but don't expect the danger to decrease so quickly. Wind will ramp up and redistribute storm snow in exposed areas into wind slabs, which is where you will probably encounter the largest and most reactive slabs. During this storm it's best to play it safe and identify any locations where more than about 6 inches of storm snow exists, and avoid these areas on slopes steeper than 35 degrees. 

    A convergence zone may direct intense precipitation to the Mountain Loop Highway area, and if this is the case, snowfall rates could be high, and shallow natural avalanches could occur during this time, as the snow struggles to adjust to the rapid change. Natural avalanches are possible with Considerable avalanche danger. Most avalanches will likely fail within the new storm snow, which will grow in size throughout the day. This means you could trigger an avalanche around 6 inches to a foot deep. However, there are a number of crusts and storm interfaces in the top couple feet where there's a small chance a failure could occur on one of those deeper layers. In general, a large variety of surfaces exist beneath the new storm snow layer we'll be getting. 

    Pay attention to red flags as your strongest indicators to avoid steep slopes. This includes recent avalanches, long shooting cracks, and whumphs. Other red flags include heavy snowfall and strong wind, both of which you could see on Thursday as well. When in doubt, stick to lower-angle slopes as the storm passes through. 

    A fresh human triggered storm slab which occurred during a storm.  Steep terrain, fresh snow, wind loading, avalanches in new snow layers.

    Photo: Alpental Pro Patrol

Avalanche Discussion

Several small natural and human-triggered avalanches were reported in neighboring zones on Tuesday. A couple avalanches failed around 2 feet deep. It's not out of the question that some similar deeper avalanches may happen again during the storm. On Wednesday the snowpack settled a bit and avalanche activity slowed. 

Snow and avalanche conditions in the zone vary extensively.  This is a day similar to others, where there's a lot of variability within the zone and from slope to slope. What you see in one location might vary quite a bit from other areas. Use this forecast as a starting point to further evaluate slopes during your day's outing. If you travel anywhere in this zone, whether you see any avalanches or not, please send in an OBSERVATION so that we know more about the conditions in the area. 

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