Spring 2017

Issued: Sun, Apr 30, 2017 at 8AM

Expires: Wed, May 03, 2017

Thank you all for another great season in the amazing Chugach!!! Daily forecasts are now finished, but this does not mean there is no avalanche danger. Please plan your spring mountain adventures keeping in mind that if it is warm enough for you to shed layers, the snow will too. Read this summary blog of spring avalanche conditions from Avalanche Canada. Keep heads up.

VAC Annual Membership and Advisory Board Meeting May 3 5-7pm  Downstairs Valdez Library   Get involved! We need your feedback, ideas, and good energy to plan for another successful season 2017-18.

Above 2,500ft None

1,800 to 2,500ft None

Below 1,800ft None

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

SATURDAY SUNDAY MONDAY&TUESDAY

DANGER SCALE

 

 

WET AVALANCHES:
Elevation:
   Below 5500′
Aspect:
   East in AM, South all day, then West in PM
Terrain:
Steep terrain near rocks and vegetation.
Sensitivity:
   Touchy when warmed.
Distribution:
   Specific.
Likelihood (Human Triggered):
  Likely when warmed.
Size:
  Small-Large
Danger Trend:
   Increasing quickly each day with warming temperatures, falling with freezing at night
Forecaster Confidence:
   Good

CORNICE FALL:
Elevation:  all
Aspect:   
all
Terrain:
corniced ridgelines
Sensitivity:   
Responsive 
Distribution:   
Specific
Likelihood (Human Triggered): 
Possible
Size:  
Small to Large
Danger Trend: 
Increasing
Forecaster Confidence: 
 Fair

AVALANCHE PROBLEM SCALE DESCRIPTORS:
Sensitivity: Non-reactive, Stubborn, Responsive, Touchy
Distribution: Isolated, Specific, Widespread
Likelihood: Unlikely, Possible, Likely, Nearly Certain
Size: Small, Large, Very Large (size scale <here>)
Danger Trend: Increasing, Steady, Decreasing
Forecaster Confidence: Good, Fair, Poor

AVALANCHE PROBLEM TOOLBOX <here>

SNOWPACK DISCUSSION:

Continental (Interior) Specific: The diurnal melt freeze cycle has created corn snowproviding for some pleasant spring riding. When the surface crusts are still frozen,  good traveling is possible. The exception being steep south facing slopes where the full depth of the snowpack has become rotten or isothermal and lower elevations where overnight temperature has not been cool enough to freeze the snow. Late in the afternoon, punchy, soft snow will limit your ability to travel and increase your risk to avalanche.

We have not seen many full depth avalanches yet, more a peeling of the onion, with wet loose and/or melt taking off layer upon layer. As the temperatures increase over the the next few weeks with less overnight freezing, expect wet slab releases possible.

Please avoid exposure to cornices. Read and listen to this sad spring cornice accident story from British Columbia earlier in April.

Sharing your observations creates an informed community.

Recent Avalanche Activity

Continental (Interior) Specific: 

  • Expect wet loose in steeps with the possibility of wet slab with no overnight freeze.
  • April 23 Natural wet slab D2.5 above Deserted Glacier, west aspect, 5800′. Lots of south and west cornice failure and wet loose activity into the Woodworth and Deserted Glaciers.

    April 14: reports of cornice failure triggering slab avalanches on steep upper elevation slopes in the Continental zone (see photo)

  • April 14 Cornice failure triggered slab avalanche in the Nelchina area    Photo: Jed Workman

  • March 31: skier triggered size D2 avalanche at 3500′ North aspect. 40-60cm storm slab failed on buried near surface facets with a old windslab as the bed surface. A possible sympathetic released lower on the same slope, with a crown depth 60-100cm, harder slab.

Recent Weather

See Maritime Zone for updated weather.

Additional Info & Media

Weather Quicklinks:

SNOW CLIMATE ZONES:

  • coastal-zone-iconMaritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • intermountain-zone-iconInter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • interior-zone-iconContinental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).

Photo of Thompson Pass

thompson-pass-ski-runs

Interactive Map of Valdez Forecast Areas w/ Many Resource Layers (Trevor Grams)

climate-zones-topoclimate-zones-satellitegoogle-earth1

Run Map of Thompson Pass Area (Sean Wisner) (2MB download)
VAC Run Map Thompson Pass

NEWS: Our region is “one of the snowiest places on earth” – Serendipity / Rendezvous snowfall record set in 1963 <here>.

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Posted in Continental Forecasts.
Sarah Carter

Forecaster: Sarah Carter