Avalanche forecast

Intermountain

Valdez Avalanche Center
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Avalanche danger

Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 8 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

The avalanche hazard is Moderate at all elevations in the intermountain zone.  It will be possible for a person to trigger an avalanche up to 16 inches in depth on specific lee slopes and cross loaded gullies. Careful route finding is important to avoid the current avalanche problem.

Forecasts are 5-day/week Wednesday-Sunday

Avalanche problems

  • Wind Slabs

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

    Strong north winds are making quick work redistributing the low density snow we have received over the past 5 days. Wind slabs up to 16" in depth will be found in cross loaded gullies and lee slopes in the mid and upper elevations. The depth of these slabs may be higher in the continental zone where snowfall totals were slightly higher. Below 3000 ft wind slabs forming on the 12/1 rain crust were showing potential for propagation in pit results. Above tree line and upper elevations expect wind slabs to be similarly reactive on top of a knife hard old wind slab.

    This avalanche problem can be managed through careful route finding and conservative terrain selection. The wind slabs will exist on terrain features that share common characteristics such as cross loaded gullies and lee slopes. Noting the direction and strength of the wind will help identify these terrain features. Look for fresh wind lips and small test slopes to determine how sensitive these new wind slabs are, and keep in mind that the depth of the slabs will vary depending upon terrain.

Avalanche Discussion

Avalanche activity in the last 72 hours:  None

Forecast Discussion:  

Over the past 5 days, dry, low density snow has been trickling in and slowly accumulating. The storm favored the continental, northern reaches of our forecast area with around 5" of new storm snow at road level in the continental zone, and only a few inches in the Maritime. Unfortunately, the new snow was accompanied by strong, sustained winds with gusts on Thompson Pass in the 70 mph range. Flagging on high peaks and ridgelines have been showing the wind is making quick work striping the new snow away. Areas that have been seeing strong winds but not as strong as in the gaps, and high elevation ridgelines will be the most likely areas you may encounter a wind slab. Gaps like Thompson pass and high elevation ridgelines exposed to the full force of these north winds will be mostly striped and the new snow will be sublimated into the air.

The December drought has left us with a thin faceted (weak) snowpack. There is a large degree of spatial variability across our forecast areas in terms of how developed the faceting is. Areas with a deeper snowpack have shown to be less faceted (stronger), while thinner areas have shown some very developed faceting (weaker). The most recent precipitation and ensuing wind is not expected to overload these weak layers yet, but once meaningful snowfall arrives we will likely have various avalanche problems.

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.  Check out the season summary tab for more information on the development of the snowpack.

 

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