Sunday-Wednesday 2/12-15

Issued: Sun, Feb 12, 2017 at 8AM

Expires: Wed, Feb 15, 2017

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

STORM SLAB:

Elevation: All
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Wide Spread
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing
Forecaster Confidence: Good

WIND SLAB:

Elevation: Above 2000 feet elevation
Aspect:
 South and west 
Terrain: 
  All terrain exposed to wind
Sensitivity:
   Responsive
Distribution: 
Specific
Likelihood (Human Triggered): 
Possible
Size: 
Small – 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

LIST OF AVALANCHE PROBLEMS <here>

SNOWPACK DISCUSSION:

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

As the new snow increases, watch for new storm snow avalanches and wind slabs.

Generally:

The new snow from the last 48 hours could activate old weak layers in the snow pack, some of which lie at the ground. Generally stable conditions before the new snow. You are most likely to encounter fresh windslab avalanches in addition to storm snow avalanches. If you determine the snow from the last 48 hours has “slabbed up” then you could create and avalanche large enough to bury and kill you.

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:  

  • No new observations reported.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  11 / 29
Ridgetop Wind Forecast (direction/mph): SE / 10-35
Snowfall (in):  2-3
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   6 / NE  12 / SE
Max Wind Gust (mph) / Direction  15 / NE  45 / NE
Temperature Min / Max (*F)  17 / 20  3 / 10

Weather Forecast:  Snow likely through out the day. Winds will be shifting between NE and SE as a new storm approaches. Temperatures may reach above 32F in the next few days, which would create a HIGH likelihood of triggering an avalanche.

Additional Info & Media

SNOW HISTORY: Valdez 2/9 AM Thompson Pass 2/12 AM
24 Hour Snow / Water Equiv. 0.4”/Trace” 0″ /0.0″
Storm Snow /Water Equiv. (2/8-9) 0.4” /Trace″ 5″ /0.2″
Current Snow Depth 37.4″ 35″
February Snow / Water Equiv. 3.1″ /0.2″ 8″ / 0.4″
Total Winter Snowfall / Water Equiv. 181″ / 16.1” 247″ / 23.1″
Snowload in Valdez 50 lbs/sq. ft.

 

SNOWFALL for LAST 24 HRS at OTHER STATIONS:
Nicks Valley at 4200 ft (in): Trace?”
Upper Tsaina at 1750 ft (in): Trace?”
Sugarloaf at 550 ft (in): Trace?”
SNOW DEPTH & WATER SURVEY (2/1/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  41.5″  9.8″
Milepost 18 43.9″ 9.5″
Milepost 29 Worthington Flats 61.5″ 16″
Milepost 37 Tsaina River bridge 42.1″ 9.3″
This survey is done the first week of each month.

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.
Kyle Sobek

Forecaster: Kyle Sobek