Saturday-Tuesday 4/22-4/25

Issued: Sat, Apr 22, 2017 at 8AM

Expires: Tue, Apr 25, 2017

Springtime conditions exist: LOW avalanche hazard in the morning transitioning to HIGH in the afternoon/evening as slopes warm from solar radiation.

Given warmer air temperatures and a poor overnight freeze, the snow will soften quickly today as the high temperatures creep ever higher in relation to last week. Steer clear of warming slopes, have a plan and expose only one at a time.

Above 2,500ft High

1,800 to 2,500ft High

Below 1,800ft High

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: 

Temperatures have been creeping ever so higher each day this week and barely dipped below freezing at Thompson Pass last night. An inversion exists, with cooler air pooling in low lying basins. The crust is likely not as resilient today and will soften quickly given solar exposure. With high temperatures at 3000′ forecasted to reach 38*F today, plan for early warming and more wet avalanche activity in the afternoon and early evening. Building clouds and limited wind will compound the warming factors. Limit exposure and avoid sloppy, isothermal slopes that will be asking for a trigger to get things moving.

Cornices have also been falling recently, which could trigger secondary, deep avalanches below.  And don’t forget about the high elevation (4000’+) northerly aspects, which are still holding good powder….seek those out, but think about the terrain you cross to get there.

Sharing your observations creates an informed community.

Recent Avalanche Activity

Continental (Interior) Specific: 

  • 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.

Forecaster: Kevin Salys