Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
Vedi sulla mappa

Pericolo valanghe

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

In sintesi

Warm and sunny conditions will continue through Sunday. Stick to simple terrain and limit your exposure to steep slopes directly overhead. Avoid traveling directly under cliffs still holding snow,  cornices, and glide cracks, especially during the heat of the day.  Areas of locally higher danger are possible - get away from steep slopes if you start seeing widespread natural avalanche activity.

Problemi valanghivi

  • Loose Wet

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

    Sunday will be the last day of warm temperatures and sun before cooler conditions return for the workweek.  Anticipate wet avalanches at all aspects and elevations, not just slopes directly facing the sun.

    Keep track of what’s above you - or what will eventually be above you - at all times.  Plan your day so you aren't forced to cross below questionable terrain in order to get back to the trailhead.

    Active signs of instability and small avalanches are warnings that bigger avalanches are possible, but you might not see anything until a big one releases naturally. Human-triggered wet avalanches are also possible. Pay attention to any snow that starts to move with you when descending.

    (4/13/2024)

    A fresh, natural wet loose avalanche on an east aspect of Table Mt at 5200'.  

    (N-WL-D1-S)

    Photo: Zack McGill - Cascade Mountain Ascents

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    In addition to wet loose avalanches, prolonged warming increases the likelihood of seeing glide avalanches and cornice fall. Glide slabs, cornices, and other hanging snow features will continue to weaken and fall off the mountain until cooler conditions prevail. Both of these dangers are isolated in distribution and fairly easy to identify. 

    Look for large cracks in the snow surface where the entire snowpack is slipping and will eventually release over the ground below,   Some cornices have already shed this year but there are plenty more of them to come down this spring. Falling cornices and shedding snow can also trigger larger wet loose or slab avalanches on the slope below.  Wet loose avalanches are much less likely when the snow surface is topped with a crust, but cornices and other hanging snow features like glide slabs and cornices won't gain much strength with cooler conditions overnight.

    (1/14/2022)

    Glide cracks are indicators where the entire snowpack is slipping on smooth ground or rock slab below. They infrequently release but they are very dangerous when they do.

Avalanche Discussion

Avalanche activity varied across the west slopes of the Cascades on Saturday. Some observers in the Baker BC in West North reported numerous wet loose avalanches on all aspects. Most were small (D1) in size, but a few were larger. An NWAC Forecaster in the Canyon Creek subzone of West North observed few fresh wet avalanches, but there were signs that plenty had already run with the first round of warming before the weekend. Recent wet loose and glide avalanches were reported from Snoqualmie Pass. Temperatures in both passes were quite high, with 58F at Stevens and highs in the low 60s at Snoqulamie. Wet, unsupportable snow was found nearly everywhere and any crust that did form overnight quickly softened by mid-morning.

Low and mid-elevation snow cover varies quite a bit with aspect. Some southerly slopes are bare up to almost 5000' in some areas, while consistent snow cover down to 3500' is found in steep, shaded valleys. While the danger is generally Low at the lowest elevations, consider it higher anywhere you find relatively smooth, consistent snow cover.

While the snow surface nearly everywhere is wet, there might still be some dry snow at the highest elevations. The likelihood is low you will find a legitimate wind slab. It’s still worth keeping an eye out for pockets of wind-drifted snow if you make it to the alpine, especially with consequential terrain below.

 This is the last avalanche forecast for the 23/24 season. NWAC will continue issuing mountain weather forecasts each afternoon at 2:30 pm through April 28. We’d like to thank each of you for reading and using these forecasts to make informed, safe decisions and for contributing to your community by submitting observations. Please continue to help support your backcountry friends by letting others know what you find in the mountains. Have a wonderful spring and summer! Lee and Irene

 

 

 

 

 

Regioni coperte