Avalanche forecast

Continental

Valdez Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche hazard is moderate above 4000 feet and low below.  Light snowfall and strong ridge top winds are expected to begin at some point today.  This will create the possibilty for human triggered avalanches less than one foot in depth on wind loaded slopes.  The hazard will be increasing overnight as snowfall begins to accumulate.  

Avalanche forecasts are issued Wednesday-Sunday.  The next forecast will be posted on 1/10.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    The avalanche hazard will begin as low today as a stable snowpack is currently in place.  The surface of our snowpack is the future concern.  Faceted (weak) snow has formed at the surface during the last 2 weeks of mostly stable weather.  This weak snow will act as a weak layer once snowfall returns to our area in earnest.

    Snowfall is forecasted for our area today through tonight with 4-8 inches expected, most of which should arrive tonight.  A moderate hazard rating has been maintained at upper elvation today due to light snowfall and strong ridgetop winds that may form shallow pockets of unstable snow during the day.  Once more than 4 inches of snow accumulates expect for deeper wind loaded slopes to become sensitive to human triggers.  If more than 10 inches accumulates instabilities will become more widespread.

    The hazard today will depend on how much snowfall accumulates and could vary within our forecast area.  Pay attention to new snowfall amounts and wind loading patterns.  

    Surface Hoar on Hippie Ridge at 4500'  1/6

    Photo: Gareth Brown

  • Glide Cracks

    • All elevations
    Likelihood
    Unlikely
    Size
    2.5–3

    Be aware that several glide cracks exist in our forecast area with a couple full depth releases occurring in the last week.  Most of these exist in the Maritime zone on southerly aspects of town mountain and Mile high at mid elevation.   A few others have been noted as far north as Billy Mitchell although they appear to be concentrated in the Maritime zone.  Glide avalanches are a strange beast that act differntly than other avalanche problems.  Full depth failure can occur independent of snowpack stability.  Or in other words, they can release even when a stable snowpack is in place.

    Since it is not possible to time their sensitivity the only way to mitigate this hazard is by avoidance.  First identify where glide cracks exist and avoid spending time beneath them.  Glide cracks are easy to identify.  They look like crevasses, but exist in non glaciated terrain.

    These do not produce small avalanches,  but rather failure will include the entire snowpack.  

    Glide release on Town mountain

    Photo: Rich Lofton

Avalanche Discussion

The main concern today is the anticipated formation of storm slabs over a layer surface hoar and near surface facets.  The actual hazard that is present in the mountains today will depend upon new snowfall amounts.  Strong winds at upper elevation today may form shallow pockets of unstable snow even with minimal accumulation during the day.  

The forecast is pointing toward snowfall holding off untill tonight.  If this is the case than our area will experience another day of low hazard.  Stong southeasterly flow is alreay in place, so the possiblilty for accumulating snowfall during the day is there.  It is likely that once the faceted snow at the surface is buried by more than a foot we will develop a persistent slab avalanche problem that will have the potential to be a concern well into the future.

Glide cracks have been observed in all three forecast zones.  Avoid travelling beneath these as full depth avalanches can release even when a stable snowpack is in place.

Valdez season snowfall: 151 inches

Valdez January snowfall: 6 inches

Valdez height of snowpack: 55 inches

Thompson Pass snowfall data is currently unavalable

46 mile height of snowpack: 68 inches

Regions covered