Tuesday-Friday 4/4-4/7

Issued: Tue, Apr 04, 2017 at 8AM

Expires: Fri, Apr 07, 2017

Friday April 14 bon fire: VAC Full Moon FUNraiser with Acoustic Avalanche @  Tsaina Lodge

Above 2,500ft Moderate

1,800 to 2,500ft Moderate

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

TUESDAY WEDNESDAY THURSDAY & FRIDAY

DANGER SCALE

WIND SLAB:
Elevation:
  Above 2500′
Aspect:
aspects lee to south-west storm wind
Terrain:
shallow snowpack near ridges, rollovers, gullies with facets underneath
Sensitivity:
   Responsive
Distribution:
   Fresh windslab where sits over facets or hasn’t yet bonded.
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: 

With all the slope testing at Thompson Pass, it seems the storm snow is bonding fairly well with the old snow beneath.  North winds transported a significant amount of snow April 2nd and 3rd. Small (D1) wind slab avalanches were triggered on southerly aspects in the inter-mountain zone. This warrants concern for unsupported wind loaded slopes on upper elevation ridgetops, gullies and convexities.

Evaluation of the snowpack down near Cracked Ice Friday showed much better bonding and no propagation. See recent observation.

Higher elevations exposed to wind have fresh wind slab formation that has been bonding well to underlying snow thus far (Q3 w/ steps), unless it is sitting on a persistently weak grain (old facets). A small collapse of newly blown in shallow slab on rocks occurred at ~3000′ on Thompson Pass on a southerly aspect.

The further north you get from the Pass, the new snow amounts decrease.

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:  

  • April 3 small D1 avalanches triggered on southerly aspects at high elevations.
  • April 2 human triggered small (D1) wind slab avalanche reported on a southerly aspect, released from thin coverage on rocks above
  • Loose snow triggered soft slab: ~30cm crown. Gully One (Vertigo)

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: Josh Hege