Avalanche forecast

Continental

Valdez Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

The avalanche hazard is Moderate at all elevations.  Human triggered avalanches are possible 1-3 plus feet in depth.  Natural wet loose avalanches are possible.

Avalanche forecasts are issued Wednesday-Sunday at 8 am. April 30 will be the last avalanche forecast of the season.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Wet Loose avalanches will be a concern today, and for the rest of the season.    The sensitivity of this layer goes through peaks and troughs throughout the day, depending on the temperature and the sun's effect.  Avoiding this problem is easy if you know what to look for.  

    Heavy new snow that fell last week has already gone through a wet loose shed cycle during clear weather on 4/19, making wet loose activity less widespread and sensitive than what we saw last weekend. On 4/23 above freezing temperatures were found to be penetrating a couple feet deep into the snowpack below 3000 feet, making wet loose avalanches possible in steep terrain on all aspects.  An increase in wet loose activity can be expected later in the day with slowly accumulating wet snow above 3000' and a saturated upper snowpack below that may become more sensitive on terrain steeper than 35° if the sun is able to win out over the clouds later in the day.

    Wet loose activity can be assessed by how wet the surface snow is and how steep the terrain is.  When there is more than 6 inches of wet snow at the surface and the slope angle is greater than 35 ° wet loose activity will be likely.   Remember this includes the slope above you as well as the one you are traveling through.  Roller balls off steep rocks are an early sign that wet loose is becoming active.

    It is recommended to plan your route to avoid steep slopes during times of day when they may be susceptible to wet loose activity.  East slopes are the first to heat up,  as the day progresses, South aspects will become active and finally West aspects will become prone in the afternoon/evening.  Avoid travel in steep terrain on slopes that are heating up.  Pay attention to the terrain above you as well as the terrain that you are travelling through.

     

     

     

    4/19- Active wet loose activity on the North Buttress of Mt Francis during sunny weather directly after heavy snowfall

    Photo: Gareth Brown

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Unusual April weather with consistent cloud cover and precipitation has built a slab above a weak layer of snow that formed during extended high pressure in late March.  Heavy snowfall last week greatly increased the sensitivity of the slab with numerous close calls reported from Helicopter ski operations and the general public.

    Persistent slab concerns from last week have decreased in depth due to natural settlement of the slab and sensitivity is expected to be lower due to warm temperatures and time allowing some bonding to occur.  This process does not happen all at once and triggering an avalanche at this layer remains possible depending upon the terrain you choose.  Steep and complicated North facing terrain above 4000' is the most likely area to trigger an avalanche at this layer (4/4) due to the potential for facets to be present.  Other aspects and elevations have shown potential for propagation at this layer as well, but the likelihood is lower due to a lack of facets.  

    Assessment for this avalanche problem is recommended on a slope by slope basis if choosing to travel in steep terrain.  Especially on slopes that are more complicated with convex features, rock trigger points and hanging snow fields.  The depth of this layer will likely not give feedback such as shooting cracks or collapsing, due to its depth.  The best way to assess a slope is by digging snow pits to identify the weak layer.  This process is time consuming and can often be misleading.  If you are unfamiliar or do not want to go through this process, it is recommended to stick with more moderate and simple terrain.

     

    (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

Avalanche Discussion

Observed Avalanche Activity last 72 hours: 

4/23- Helicopter skier was caught and carried in small avalanche involving windloaded snow .  No injuries SS-ASc-R1-D2

Forecast Discussion:

The snowpack is rapidly transitioning to a spring setup.  Wet loose avalanches are the main concern and should be treated seriously on slopes steeper than 35° that are becoming active or have wet snow.  Another spring hazard is cornices.  This is the time of year when these overhanging chunks of snow fail naturally with more regularity.  Large loads such as cornice fall have the potential to trigger deep avalanches.

In high north facing terrain where less settlement has occurred, and bonding happens at a slower pace, persistent slab avalanche concerns remain involving the cumulative build up of the April snowfall (4/4).   The interface of the 4/4 layer has been observed at multiple elevations and aspects with different varieties of snow grains at the interface, ranging from old temperature crusts on solar aspects, large melt forms below 4000' and facets on high elevation North facing terrain.  All of these interfaces have shown potential for propagation, which means that the main concern in the snowpack has been how this slab has developed with little solar input not  necessarily the weak layer.  Although the presence of facets will be the most likely area to trigger a slide.  The variety of interfaces have all shown that the snowpack below has been resistant to accept the slab above, at least more so than what you would typically expect this time of year.  During the rare times this month when the sun has come out the April slab has become more sensitive and human triggered and natural avalanches have been the result.  

As mentioned above the most likely place to trigger an avalanche involving the April slab will be on high north facing terrain that is steep and complicated where facets exist.  But mid elevations could also be reactive during times when above freezing temperatures are able to penetrate deeper into the snowpack.

Additional Information:

Avoid Cornices. This is the time of year when cornices begin to fail naturally.  Cornice fall will have the potential to create 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- 4/24 24 hour Snow Water Equivalent Inches Height of Snow April Snowfall Inches Season Total Snowfall Valdez    0    Trace    27      2     N/O     Thompson Pass   N/O    0   N/O     N/O    ~500 Nicks    0    0    156    N/O N/O 46 Mile    0     0   10    10 N/O

Regions covered