Bollettino valanghe

Continental

Valdez Avalanche Center
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Pericolo valanghe

Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

The avalanche hazard is CONSIDERABLE at all elevations.  Multiple avalanche problems exist.  Human triggered avalanches are likely 1-3 feet in depth and could exceed 5 feet in depth in specific areas.  Natural avalanches are possible today

Avalanche forecasts are issued Wednesday-Sunday at 8 am.

Problemi valanghivi

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    2.5–3

    Consistent snowfall through the majority of April has built a slab that is unstable at upper elevations.  The depth and type of weak layer is highly variable ranging from 2-5 feet in depth dependent upon location.  Before yesterday this layer was thought to exist on just shaded aspects.  Numerous natural slab avalanches on solar aspects occurred yesterday, proving this theory incorrect.  This weak layer is more widespread than previously thought, the weak layer type and depth is variable.  On shaded aspects, faceted snow exists that was created during the extended March high pressure.  On solar aspects a melt freeze crust is acting as an effective bed surface with small wet loose producing  natural slab avalanche activity during the day yesterday.

    This variability in the weak layer shows that the steady buildup of snow during April without solar input is the main issue.  One sunny day and a clear night is not enough to significantly lower the hazard with this unique situation.  Dangerous avalanche conditions are expected to continue today.

    There is plenty of moderate terrain in our forecast area where users can enjoy the new snow without worry of triggering a dangerous avalanche.  Steep and complicated terrain is the major area for concern today.  

    It is strongly encouraged to keep terrain choices moderate and simple.

    (4/15/2025)

    Hiker triggered avalanche on Local Spines . Crown depth 3-4 feet/ 500-600 feet wide/ multiple step downs.

    SS-AFu-R3-D3

  • Loose Wet

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

    Wet loose is a major hazard today in areas that are receiving direct sun.  Cloud cover has already moved into the coast with interior areas remaining clear as of 6 am.  The wet loose hazard will depend on how much the sun is able to break through the clouds.  Observations from yesterday showed the snowfall that has accumulated during April to be very reactive to solar input with widespread wet loose activity on sunny slopes.  Some areas did not freeze overnight while others saw a superficial freeze.  Expect a continuation of yesterdays wet loose shed if the sun wins out over the clouds.

      Steep rocky areas will be the first to be affected  as the suns energy is more efficiently absorbed by the dark color of rocks and then transmitted into the surrounding snow.  The solar facing rocky terrain that hangs above a lot of our steep ramp terrain will be active during the heat of the day.   Wet loose avalanches may be able to create enough force to step down to deeper layers in the snowpack.

    Low elevations are expected to become isothermal on all aspects.  Avoid travel in steep terrain at low elevations and slopes that are heating up.  Pay attention to the terrain above you as well as the terrain that you are travelling through.

     

     

     

    (4/2/2025)

    Skier triggered wet loose avalanche near Worthington Glacier toe.

    Photo: Gareth Brown

Avalanche Discussion

Observed Avalanche Activity last 72 hours: 

4/19- Natural and human triggered avalanches were reported 

4/18- Helicopter skier triggered avalanches were reported with wide propagations.  Natural avalanches occurred in direct response to the sun coming out

4/15- Numerous avalanches were triggered at the 4/4 deep persistent weak layer size D2-3 involving skiers, helicopters, hikers, and snowmachines

Forecast Discussion:

DANGEROUS AVALANCHE CONDITIONS EXIST.    Some settlement of the most recent storm snow occurred yesterday, however instabilities are expected to remain today within the most recent snowfall and deeper in the snowpack.

The main concern revolves around the steady build up of storm snow over the last 2 weeks on top of a weak layer of snow that was formed by extended clear weather in March.  A lack of sun this month has created a unique situation where instead of the snowpack being able to slowly settle and transition to a spring snowpack, continued snowfall has been building the snowpack with high elevations seeing snow heights peak for the season.  When the strong April sun comes out the upper snowpack undergoes rapid change attempting to reach equilibrium.  As the snowpack attempts to adjust, instabilities will be present.

The sun is not the only thing that has been restricted in April.  Skiers and snowmachiners have also had a lot of down days.  Thompson Pass is extremely busy right now with travelers, events and heli skiers.  All of these users are going to be extremely anxious to access the new snow as sun has been a scarcity.  The human factor today is a major concern and should be its own avalanche problem that would sit in the #1 slot.  

The combination of snowpack conditions, weather history and human factor all combine to make today an elevated hazard day.  There will be lots of great snow to enjoy on moderate terrain today.  Conservative terrain choices are strongly encouraged.

You can reduce your hazard by doing the following: 

Limit travel on or below slopes steeper than 32 degrees

Travel with partners who are competent in snowpack assessment and rescue techniques

Travel one at a time in avalanche terrain and use a spotter. 

Limit travel in avalanche terrain when hazards are elevated

Make travel plans based on your ability to handle unexpected or hazardous situations. 

Additional Information:

Avois Cornices. This is the time of year when cornices begin to fail naturally.  Cornice fall will have the potential to create very large destructive avalanches.

A weather and snowpack season history is available by clicking on the Season Summary tab, which is located below the bottom line statement once you have entered the full forecast.

Season Snowfall Data

Location 24 hour Snowfall Inches- 4/20 24 hour Snow Water Equivalent Inches Height of Snow April Snowfall Inches Season Total Snowfall Valdez    0    0    35      2     N/O     Thompson Pass   0    0   N/O     N/O    ~500 Nicks    0    0    156    N/O N/O 46 Mile    0     0   14    10 N/O

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