Wednesday-Saturday 1/12-1/15

Issued: Fri, Jan 12, 2018 at 8AM

Expires: Mon, Jan 15, 2018

Moderate danger does not mean no danger.  Keep your eye out for bulls-eye clues and regroup out of harms way.

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

WEDNESDAY THURSDAY FRIDAY & SATURDAY

DANGER SCALE

WIND SLAB:
Elevation:
   Above 2000′
Aspect:  
 Lee of ridges, gullies, ridgetops
Terrain: 
  All terrain exposed to wind
Sensitivity:
   Stubborn
Distribution:   
Specific
Likelihood (Human Triggered):   
Possible
Size:   
Small – Large
Danger Trend:
   Steady 
Forecaster Confidence:
   Fair

PERSISTENT SLAB:
Elevation:
   Above 2500′
Aspect:
   All
Terrain: 
  35+ degrees steepness
Sensitivity:
   Stubborn
Distribution:   
Specific
Likelihood (Human Triggered):   
Possible
Size:   
Small – Large
Danger Trend:
   Decreasing 
Forecaster Confidence:
   Poor

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:
The big concern is the near surface faceting <info here> and surface hoar now buried with the New Year’s storm snow. See Observations <here>.

North of the highway at Milepost 34-5 Sunday January 7 revealed numerous significant whumps and snowpack tests consistently produced easy shear results two feet from the snowpack surface running on the Dec. 26 surface hoar.

Two to four feet of storm snow has fallen since Jan 1. During the January 1-3 storm strong southerly winds drifted windslabs to waist deep at Thompson Pass. Strong northerly outflow winds to 60mph January 4-9 have built pencil hard windslabs on exposed slopes.

On behalf of the snow sports community, thank you for sharing your observations!

Recent Avalanche Activity

A few windslab avalanches to size D2 where observed along the highway corridor over Thompson Pass between Mileposts 23 and 28 on Tuesday January 9.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  23 / 15
Ridgetop Wind Forecast (direction/mph): NE / 8-36
Snowfall (in): 1-3
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   ~ / ~  17 / ENE
Max Wind Gust (mph) / Direction  ~ / ~  34 / NE
Temperature Min / Max (*F)  ~ / ~  -9 / 18

Weather Forecast:   Warmer and overcast with intermittent flurries.  Visibility decreasing into the evening.  Snow flurries through the weekend depositing a total of 1′ (30cm) of snow.

Additional Info & Media

SNOW HISTORY: Valdez 1/10 AM Thompson Pass 1/10 AM
24 Hour Snow / Water Equiv. 0.3”/ 0.03″ 0″ / 0″
Storm Snow /Water Equiv. (1/1-3) ” / ″ 30″ / 3.0″
Current Snow Depth 25″ 72″
January Snow / Water Equiv. 13.15″ / 3.64 ″ 32″ / 3.1″
Total Winter Snowfall / Water Equiv. 77″ / 19.86” 239″ / 27.3″
Snowload in Valdez 42 lbs/sq. ft.

 

SNOWFALL at OTHER STATIONS:
LAST 24 HRS / STORM TOTAL / STORM WATER EQUIV.:
Nicks Valley at 4200 ft (in): ~” / ~” / ~”
Upper Tsaina at 1750 ft (in): ~” / ~” / ~”
Sugarloaf at 550 ft (in): ~” ~” / ~”
SNOW DEPTH & WATER SURVEY (2/1/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  ″  ″
Milepost 18
Milepost 29 Worthington Flats
Milepost 37 Tsaina River bridge
This survey is done the first week of each month.

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 Continental Forecasts, Intermountain Forecasts, Maritime Forecasts.

Forecaster: Ryan Van Luit