Bulletin d’avalanche

Continental

Valdez Avalanche Center
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Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 7 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

The avalanche hazard is Considerable above 2000 feet and Moderate below.  New snow continues to stress weak snow in the mid elevation band and fresh storm slabs are building at all elevations.  Human triggered avalanches are likely 1-3 feet in depth. Natural avalanches are possible.  The hazard will be on an upward trend as new snow continues to accumulate.

Public avalanche forecasts are issued Wednesday-Sunday at 8 am.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    The most likely avalanche problem a person will encounter today is storm slab avalanches.  The most dangerous avalanche problem will be triggering a persistent weak layer (see problem 2) in the mid elevation band.  

    Valdez received 4" of new snow in the last 24 hours as of 5:30 am with Thompson Pass likely on the lighter side.  We can expect an additional 4-10 inches of snow today with the Maritime zone seeing the higher end of accumulation.  The new snow is low density and will easily be redistributed by any wind that occurs.  Expect instabilities at the surface as well as deeper down.

    Except for a few short breaks in precipitation, snowfall has been fairly steady over the last 10 days.  Storm slabs are building without time for the snowpack to adjust.  Expect to find various density changes within the new snow that will be capable of producing avalanches in steep terrain.  Areas where the wind has redistributed the new snow and stiffened the surface will be the most likely areas to trigger an avalanche.  

    Watch for signs of instability such as shooting cracks and collapsing.  These are bullseye indicators that unstable snow exists and moving to terrain <30° is a good idea.  Keeping terrain choices simple today and avoiding large avalanche paths is recommended.

     

    Photo: NWS

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–3

    We have a dangerous snowpack setup in specific areas.  Very weak snow exists below 3500' and is reactive to human triggers in open terrain (bush free).  Luckily this weak layer of snow has been presenting obvious signs of instability.  Where signs of instability are observed, we strongly suggest keeping to mellow terrain without overhead exposure to large slopes.

    This avalanche problem is capable of producing avalanches large enough to injure, bury or kill a person.  Natural avalanches will become increasingly likely as snow continues to accumulate and temperatures rise through the week.

    Deep Persistent Slab:  Above 3500' the structure and strength of the snowpack is very different.   Weak snow exists here as well near the base of the snowpack, but the major difference is that this weak snow is capped by very hard wind slabs rather than a fragile rain crust.  Another difference is that the distribution of the hard slabs is extremely variable making assessment challenging.  At this point, affecting snow beneath these old wind slabs is unlikely, but the consequences would be high.  Sensitivity of this layer is expected to increase over the coming days with the arrival of a significant snowfall event forecasted Thursday-Friday.

     

    (1/3/2026)

    Facets on the underside of the 12/1 rain crust

    Photo: Gareth Brown

Avalanche Discussion

Avalanche activity in the last 72 hours: No

Forecast Discussion: 

This is an exciting week of weather for our area, with the main event scheduled to begin on Thursday.  Stress is slowly increasing on a snowpack with multiple issues.  That stress is expected to ramp up in the next 36 hours.  Heavy loading of the snowpack will be a good thing in the long-term, but will create significant hazard while the snowpack is being loaded.  Be patient during this week of heavy precipitation and if you decide to travel in avalanche terrain today keep terrain choices simple, maintain good communication with your group and give large avalanche slopes a wide berth.

It will be possible to encounter multiple avalanche problems today.  Assesment will be a challenge especially for those that dont have a firm understanding of the evolution of our snowpack.  To summarize a complicated snowpack is difficult, but this is what we should internalize:  The December drought caused our snowpack to weaken (facet).  Strong winds created variable snow depths across terrain making weak snow variable in regard to its development, distribution and the strength of overlying layers.  Despite this variability the mechanism for creating the weak snow is the same everywhere, a month of cold temps and thin snowpack.  This week snow will be tested over the coming days.  Stay out of the way while the test is in process.

Additional Details:  Be aware that the new snow is masking what was bare ground last week in some areas.  Large expanses of bare ground exist near Thompson Pass in popular terrain such as Moonlight, Loveland, Oddessey, and Catcher's Mitt.  Use caution in all terrain above 3000' to avoid hitting rocks.

There is very little field data from the Maritime zone due to low snow coverage and thick brush restricting access.  Check out the season summary tab for more information on the development of the snowpack.

 

Régions couvertes