Thursday-Sunday 4/27-4/30

Issued: Thu, Apr 27, 2017 at 8AM

Expires: Sun, Apr 30, 2017

Springtime conditions exist: avalanche danger increases with daytime warming and direct solar radiation.

Expose yourself to avalanche prone terrain only when necessary. Even if you are standing on flat ground, the upper slopes above you are harboring large amounts of weakening snow that could travel great distances if it happens to release.

Above 2,500ft Considerable

1,800 to 2,500ft Considerable

Below 1,800ft Considerable

Degrees of Avalanche Danger ?

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

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

THURSDAY FRIDAY SATURDAY&SUNDAY

DANGER SCALE

 

 

WET AVALANCHES:
Elevation:
   Below 6000′
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:

intermountain-zone-iconInter-Mountain (Transitional) Specific:

Warm temperatures yesterday led to poor overnight freezing of the snowpack. When you add the weight and weakening properties of rain on snow, natural avalanche activity from above is possible. Wet avalanche can travel greater than expected distances and are incredibly dense and powerful. Limit any exposure to overhanging snow and evaluate the snow underneath you as you travel through the mountains. It may be difficult to see signs of red flag activity when the visibility is poor. If the snow is shifting easily under skis or machine and you can easily sink deep into underlying layers of snow, consider calling it a day. Large, crushing, wet slabs can be triggered quite deep this time of year. There is a chance for some snowflake accumulation up high, but it just depends on the air mixing patterns and wind.

Sharing your observations creates an informed community.

Recent Avalanche Activity

intermountain-zone-iconInter-Mountain (Transitional) Specific:  

  • April 23 Natural wet slab D2.5 above the Deserted Glacier at 5800′ on a west aspect

    April 24 Fresh wet slab above Deserted Glacier Photo: Sarah Carter

  • April 12-16 With more direct sun, more wet loose releasing out of steep, south aspects entraining snow to D2.5, sometimes to ground
  •  April 18th  “Things are coming unglued out there” Photo: Jeremy Martin
  • April 17th Large avalanche on, “The Wall/Tomahawk” caused by rockfall Photo: Jed Workman

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 Intermountain Forecasts.

Forecaster: Kevin Salys