Lawinenlagebericht

Continental

Valdez Avalanche Center
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Lawinengefahr

Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
2 · Mässig
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Kernpunkte

The avalanche hazard is moderate but will increase with additional snow loads later today into this evening.  Triggering avalanches 1-2 feet deep will continue to be possible. Watch out for windslabs or wind stiffened storm snow that may have increased sensitivity.  Additional snow loads will begin stressing our weak snowpack, creating the possibility for larger avalanches. If you observe significant new snow accumulation today, expect the hazard to be increasing.

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

Lawinenprobleme

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    1.5–2.5

    Recently formed storm and windslabs are stressing a weak lower snowpack throughout all of our forecast areas. Buried knife hard windslabs formed in December are bridging the faceted base in many areas, providing a bit of support for layers above. The thickness of this buried slab varies from just a few inches to 2 feet thick in some locations. Areas where the buried December windslab is thinner will be the most likely places to trigger a persistent slab. Probing or digging will be required to assess this. Moderate increases in stress over the last week have not produced any avalanche activity, but significant collapses have been evident in several areas. 

    Later today, into this evening, we will see a significant load on this weak snow with an increasing chance of avalanche activity through the weekend. Large interconnected slopes over 32 degrees loaded by deep storm snow or thick windslabs may be able to produce destructive human-triggered avalanches on persistent weak layers. The chances of this will increase with additional snow loads this weekend. Pay attention to how the recent snow has loaded the areas you travel in today and use protocols to avoid exposure to suspect slopes. 

    Below about 3500 feet, the 12/1 rain crust is creating an additional persistent weak layer that will be contributing to avalanche hazard with continued loading.

    Wind Slab: Recently formed windslabs near the summit of Thompson Pass may be sensitive to Human Triggers today. Significant windslab formation is expected to be limited to the area adjacent to the pass summit, with less wind effect to the North.

    Storm slab: In non-wind-affected areas, there is little cohesion within the dry storm snow; however, a few density changes within new snow have been producing failure. Expect the possibility of triggering small soft slab avalanches on isolated steep terrain. 

     

Avalanche Discussion

Avalanche activity in the last 72 hours:  None

Forecast Discussion: 

The most significant snowfall of the season will begin affecting our area later today. The avalanche hazard has been left at moderate since significant impact will likely occur this evening into tonight. If impactful snowfall arrives earlier, you can expect the hazard to rise to Considerable due to increased loads on persistent weak layers in our snowpack. There is a bit of uncertainty regarding the amount of stress it will take to produce failure of the buried December windslabs, but this next storm will likely stress this situation to failure at some point. Hopefully we recieve enough load to crush and settle our weak snowpack. Stay tuned as we monitor the effects of this storm. 

 If you haven't been checking the forecast regularly, this is a good time to start, as we head into a more active period with the potential for rapidly changing conditions.

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 no 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.

 

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