Bollettino valanghe

Continental

Valdez Avalanche Center
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Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

The avalanche hazard is moderate at all elevations.  Last weekends snowfall is beginning to setlle however instabilities may still exist.  Human triggered avalanches are possible 2-3 feet in depth.   Small wet loose natural avalanches are possible on southerly aspects.

Problemi valanghivi

  • Persistent Slabs

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

    New snowfall from last weekend has shown signs of settling and has been observed to be right side up by many observers with a lack of signs of instability.  Despite all these positive signs human triggered avalanches remain possible 2-3 feet in depth.  Storm totals were in the 2-3+ foot range and were deposited on a layer of near surface facets/surface hoar (weak snow) that was found to be widespread.

     In some locations, the 2/9 facets existed above a hard bed surface of old windblown snow created by the outflow winds at the beginning of the month.  In other areas that were previously protected this hard bed surface does not exist. We may be in a situation where signs of instability are not present due to the depth of the new snow, even though a potentially weak layer may exist.  A lack of  avalanche activity in the Thompson Pass area indicates that this weak layer did not cycle naturally and is now buried in our upper snowpack.  

    Further assessment of this situation is necessary with observations from more areas before we can list this problem as unlikely.  Use terrain progression today along with ECT tests to assess snowpack stability.   Terrain progression is a process of starting on smaller slopes with low consequences to assess stability and slowly moving towards steeper terrain only once good stability can be confirmed.  At this point, human triggered avalanches that do occur would probably be initiated from steep terrain (>35°) and/or unsupported slopes.  However, remote triggers from flat areas below large slopes can not yet be ruled out as a possibility.

    Light to moderate southerly winds along ridgetops will build deeper more cohesive slabs that will put more stress on the 2/9 facets, making human triggers more likely in specific locations.

    (2/8/2024)

    Faceted snow was created during clear, calm, cold 2/6-8.  This snow is now buried by 2-3 feet of snow from 2/9-10 and is currently a layer of concern.

    Photo: Gareth Brown

  • Loose Wet

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

    Temperatures above freezing are once again forecasted for coastal locations.  Wet loose natural activity is expected during the heat of the day at low elevations on southerly aspects.  This activity will begin where rocks or vegetation exist as the sun's heat is more readily absorbed in these areas and transferred into the surrounding snowpack.  If you choose to travel on southerly aspects at low elevation today pay attention to the effect the sun is having on the surface snow.  Is the surface becoming Moist?  Is this wet snow more than a few inches deep?   If the answer is yes, then avoid traveling on and exposing yourself to steep solar aspects.  Even small avalanches can have the power to knock you off your feet or bury you if you are in a terrain trap.

Avalanche Discussion

Today will be only the second day of clear weather after a significant snowfall event that was deposited on weak/faceted snow.  Even though our mountains are known for their amazing ability to bond and heal weak layers, caution is advised.  Allow the snowpack time to settle and adjust to its new load.  Investigation of the bonding at the new/old interface is highly recommended as stability may vary among different locations.  Winds are forecasted to be light, however, watch our for pockets of wind loaded snow below high elevation ridgelines and in wind channeled terrain created by light to moderate southerly winds.

Another thing to keep in mind is this clear weather is coinciding with warmer temperatures for the first time of the year.  This is a red flag in itself as the snowpack adjusts to the heat of the sun.  Cornices likely grew over the weekend.  There is a chance we see some cornice failure this week as warm temps affect these.  Moderate wet loose point release activity was observed on southerly aspects at lower elevations yesterday.  This is expected to continue today and may be more significant as heat penetrates deeper into the snow.  Avoid steep southerly aspects at low elevations during the heat of the day or if the surface is becoming moist.

 Glide cracks have been observed in all three forecast zones.   Some of these have recently been obscured by new snowfall, making them more difficult to identify.   Avoid traveling beneath these as full depth avalanches can release unexpectedly.

Valdez season snowfall: 240  inches

Valdez February snowfall: 34 inches

Valdez height of snowpack: 84 inches

Thompson Pass snowfall data is currently unavailable

46 mile height of snowpack: N/O

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