Monday-Thursday 4/24-4/27

Issued: Mon, Apr 24, 2017 at 8AM

Expires: Thu, Apr 27, 2017

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

Avoid steep terrain and cornice exposure in the afternoon.

Above 2,500ft High

1,800 to 2,500ft High

Below 1,800ft Moderate

Degrees of Avalanche Danger ?

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

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

MONDAY TUESDAY WEDNESDAY & THURSDAY

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:  The spring shed is in progress. Over the past week, daytime temperatures have reached into the 50s in the valley bottoms. Most of our remaining Chugach snow has been freezing at night and thawing during the day. Last night was the first night it did not freeze at Thompson Pass. This means crusts and lots of isothermal snow below 3000′.

Having just finished a 19-day dry spell, the bit of rain and snow this week will freshen our snow world. If the 1/4″ of precipitation comes our way, we can expect rain to about 4000′ with snow above. With warm temps the new snow should bond quickly. An exception will be upper elevations with a sun crust come bed surface. When the sun pops out again toward the weekend, expect fresh loose avalanches and the possibility of new wet slab.

A tour out to the Woodworth and Deserted Glaciers April 23 revealed many cornice failures, active wet loose avalanches in the heat of the sun, and some fresh wet slab avalanches peeling down to the last storm snow interface.

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