Sunday – Wednesday 3/26-29

Issued: Sun, Mar 26, 2017 at 8AM

Expires: Wed, Mar 29, 2017

Avalanche Center Tsaina Lodge Spring Full Moon Bon Fire FUNraiser

Friday April 14 presenting Acoustic Avalanche

Above 2,500ft Moderate

1,800 to 2,500ft Low

Below 1,800ft Low

Degrees of Avalanche Danger ?

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

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

SUNDAY MONDAY TUESDAY & WEDNESDAY

DANGER SCALE

 

 

WIND SLAB:
Elevation:  
Above 3000′
Aspect:
   Lee to northerly winds
Terrain:
 Near ridgelines, rollovers, and gully walls
Sensitivity:
  Stubborn
Distribution:
 Specific
Likelihood (Human Triggered):
 Possible
Size:
 Small – Large
Danger Trend:
  Decreasing
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: 

Poor structure of the snowpack, strong snow sitting over weak snow, remain the concern, both newer windslabs and whole basins whumphing in areas on the northerly and easterly outreaches of our Inter-mountain zone, and into the Continental zone. Deep persistent slab problems are challenging to predict: have a lower probability of triggering, but with consequences.

Last week’s series of convective storms across the region deposited significant variation of new snow throughout the region. Cordova reported 8 inches at sea level and 2 feet above 1000′. Valdez received 2 inches with 1 foot at Thompson Pass and in the upper elevations of the maritime snow climate zone. Kenny Lake has recieved an inch or two almost daily through the past week.

There’ve been numerous natural and human triggered soft slab avalanches over the past week, mostly D1-2. However, with increasing solar radiation, >D2 natural releases are observed off E-S-W aspects.

Find more photos and observations at the bottom of the page. Sharing your observations creates an informed community that everyone benefits from at some point.

Recent Avalanche Activity

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

  • March 25 repports of upper elevation (>4500′ elevation) human triggered windslabs to a foot thick releasing off steep slopes.
  • March 25: Several reported natural and one remotely triggered soft slab avalanche up to D1.5 on southerly aspects between 4,500′-5,500′.

    Loose snow triggered soft slab: ~30cm crown.

  • Reported March 24: Many significant collapses (as large as whole basins whumphing) in areas on the northerly and easterly outreaches of our Inter-mountain zone, and into the Continental zone. Deep persistent problem RED FLAG!!!
  • March 24: Small D1 R1 skier triggered wind slab on the west facing wall of Snatch (Gully 2). Recently loaded by NE outflow winds
  • March 22: Small skier triggered slide in Nick’s, size D1, west facing, wind loaded slope.

 

Recent Weather

See Maritime Zone for updated weather.

Additional Info & Media

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Thompson Pass RWIS weather station <here>
  • MP 30 Nicks (Happy) Valley weather station at 4200 feet <here> (scroll to Nicks Valley)
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>
  • Further weather resources <here>

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.
Pete Carter

Forecaster: Pete Carter