Lawinenlagebericht

Continental

Valdez Avalanche Center
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Lawinengefahr

Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Veraltet — dieser Lagebericht ist 8 months ago abgelaufen. Du siehst vergangene Verhältnisse, nicht den aktuellen Bericht.

Kernpunkte

The Avalanche hazard is moderate due to lingering windslabs. Expect the possibility of human-triggered avalanches in isolated areas where windslabs overlie weaker snow.  Natural avalanches are unlikely. 

Avalanche Forecasts will be issued 3 days/week during December.  The next forecast will be issued on Friday, December 12th.  5-day/week forecasts will return in January once 2026 funding comes through.

Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    For the last week, wind has been a primary driver of avalanche hazard throughout our zones. Windslab ages range from a week old to more recently deposited. Older windslabs can be identified by their drumlike feel and rock-like hardness and are not likely to be reactive without a large trigger. More recently deposited windslabs found in isolated areas may be softer, thinner, and more susceptible to a human trigger.  Observations show windslabs to be isolated and gaining strength, but there is a lingering possibility of triggering a sensitive pocket 1-2 feet deep that could bury or injure a person.  Natural windslab avalanches are unlikely.  

    Below 3000 feet a rain crust that formed on 12/1 may prevent the wind from eroding the snowpack below that level.  This rain crust will act as a smooth sliding surface on lee slopes where new wind slabs are formed.

     Avoid terrain traps and travel in gullies.  Shooting cracks will be a sign of instability that indicates you are on unstable snow and should avoid slopes steeper than 30°.

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1–2

    Our early-season snowpack has shown a couple of weak layers of facets within the top 3 feet of the snowpack.  Reactivity in these layers has varied in multiple observations, so there is a bit of uncertainty about how they will react in any given location/situation. Our most recent pit tests have not produced significant results, but a couple of planar interfaces topped with facets are readily identifiable. In the short term, there will be little additional stress applied to these layers; however, cold dry weather will be promoting faceting and weakening of these interfaces. There is an isolated possibility that a small slab avalanche could step down into one of these layers, causing a larger, more destructive avalanche. 

Avalanche Discussion

Avalanche activity in the last 72 hours:  Nothing in this time frame, but numerous natural slab avalanches from earlier this week. 

Forecast Discussion:  

For the last week, our weather has been dominated by cold, dry, and windy conditions. Recorded gusts in Valdez and Thompson pass were up to 70mph and 92mph, respectively. Today marks a break in the wind before another round of storm to hurricane force winds hits this weekend. Expect continued scouring and sublimation of the snowpack. Slab formation will be reduced compared to last week since there is limited snow for transport at the moment.  Expect Dangerous windchills and variable snow conditions if you get out this weekend.

We are continuing to gain information about our mid-snowpack structure, but there is still a bit of uncertainty in this area. In some areas, especially below 3500 feet, the mid snowpack is still faceted with a couple of notable planar interfaces within the top 3 feet. Current weather conditions will promote faceting and weakening of the snow at these interfaces. Higher elevations show a deeper, stronger snowpack in protected areas, but thinner faceted snow can still be found on scoured ridges and rocky slopes. Additional observations above 4000' are necessary to reduce uncertainty regarding the upper elevation snowpack. 

Additional Details:  There is no field data from the Maritime zone due to low snow coverage and thick brush restricting access.  Numerous Glide avalanches have released in the Maritime zone in the mid elevation band.  Some of these may have failed without previous visible glide cracks.  Avoid travel below glide cracks as they can fail at any time.  Their likelihood of failure is independent of the snowpack stability.

 

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