Avalanche forecast

Maritime

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 wet loose avalanches will be possible at low elevations and wind slabs at upper elevations.  Wet loose hazard will depend on how much precipitation arrives today and whether it falls as snow or rain.

Avalanche forecasts are issued Wednesday-Sunday; the next forecast will be available on 12//24.  In the meantime watch for the development of new storm slabs as moderate snowfall is expected Monday-Tuesday.

Avalanche problems

  • Loose Wet

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

    Temperatures have risen above freezing overnight at low elevations on the south side of Thompson Pass.  Light rain is forecasted today that will fall on what was previously dry snow at the surface.   Wet loose avalanches will be a concern in steep and open low elevation terrain today.  Thick vegetation exists at low elevations and will prevent wet loose activity from gaining momentum in most areas.  In isolated areas where open slopes exist at low elevation, and rain on snow is occurring wet loose activity will be something to watch out for.

    The potential for wet loose activity can be judged by digging into the snow to see how deep moisture has penetrated into the snowpack.  The depth of moisture in the snow will determine how much entrainment is possible.  This combined with the size of the slope will determine the destructive potential of wet loose activity.  Another good way to test for wet loose potential is to drag your ski pole basket along the surface of the snow down a slope to see how much entrainment occurs.  Pay attention to how wet the surface snow is and the terrain you are traveling on as a whole. What is above you?  What kind of slope are you on?  What is below you, is there a terrain trap?

     

  • Wind Slabs

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

    Yesterdays winds were not as strong as forecasted and distribution was not as widespread as well.  It can still be expected that some new wind slab formation occurred but to a lesser degree than what was previously expected.  Watch for areas where the surface snow has been redistributed into deeper pockets and use test slopes to assess the sensitivity of these areas. A couple of inches of new snow has fallen over the last 24 hours and a couple more is expected today.  This will add to wind slab depth in specific areas, however winds are not forcasted to be strong or widespread today.

    Wind slabs can be identified visually and by feel.  This avalanche problem may have a rounded pillowed look, or a rippled texture.  Where slabs exist the snow will be stiffer on top than the snow below and may show signs of instability, such as shooting cracks and collapsing.  Pay attention to the degree at which soft snow at the surface has been redistributed by the wind in the area you choose to travel.

     

     

Avalanche Discussion

Observed Avalanche Activity last 72 hours: 

NONE

Temperatures are on the increase on the south side of Thompson Pass and at upper elevation.  Rain on snow at lower elevation will create a wet loose hazard today.  The consequences of wet loose activity is expected to be mitigated by thick vegetation in most areas.  A couple inches of snow has fallen over the last 24 hours and a similar amount is expected today.  This will add to wind slab depth along upper elevation ridgelines and in cross loaded terrain near the top of Thompson Pass.  Surface hoar was buried yesterday, but is not a current concern due to insufficient snow load on top and has only been observed below brush line where thick vegetation would prevent a continuous slab from forming in most locations.

In wind protected areas the snowpack has been going through a slow and steady process of becoming more stable.  The 12/15 storm has been showing signs of good bonding with the 12/10 rain crust below 3500' as well as with the dry snow that exists at the interface above 3500'.    The Novemmber wind board is breaking down and no longer has any reliable bridging characteristics.  Facets do exist under this layer, however the current snowpack is not under stress compared to its relative strength.  This will be a layer to watch once heavy precipitation returns to our forecast in hopefully the not-too-distant future. 

Continue to avoid Glide cracks in the area where they exist from Nick's Buttress through Cracked Ice at mid elevation.

If you travel in the Continental zone today, exercise extra caution as there is very limited field data from this location.  It is unclear as to whether deep slab instabilities exist, however it is a possibility.

If you get out in the mountains today consider leaving an observation to help increase the understanding of current snowpack stability.  

A weather and snowpack season history is available by clicking on the Weather History tab that is located above the bottom line statement once you have entered the full forecast.

Season Snowfall Data

Location 24 hour Snowfall Inches- 12/22 24 hour Snow Water Equivalent Inches Height of Snow December Snowfall Season Total Snowfall Valdez    0 N/O    12     27     35 Thompson Pass    2 N/O   N/O    N/O    N/O Nicks    2 N/O    44    24 N/O 46 Mile    1   N/O   14    5 N/O

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