Tuesday-Friday 1/9-1/12

Issued: Tue, Jan 09, 2018 at 8AM

Expires: Fri, Jan 12, 2018

Above 2,500ft Considerable

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 2000 feet elevation
Aspect:  
 Lee to clear weather northerly outflow winds Thursday and Friday January 4-9.
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 feet elevation
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>; many thanks to those submitting for which we’re all much obliged.

North of the highway at Milepost 34-5 Sunday January 7 revealed numerous loud whumps heard by all over their snowmachines. and snowpack tests consistently produced easy shear results two feet from the snowpack surface.

Two to four feet of storm snow has fallen since the New Year. During the storm strong southerly winds drifted windslabs to waist deep at Thompson Pass. Forecast northerly outflow winds will build new windslabs; anticipate finding hard windslab over wind exposed terrain.

A few small storm slab releases have been observed along the highway through the inter-mountain snow climate zone, with the releases running on the Boxing Day surface hoar.

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

Multiple persistent slabs up to size D2+ ran on DOT ridge in addition to North Odyssey and the Tsaina Valley. These persistent slabs are releasing on the Christmas/Near Years Surface Hoar (Hoar Frost) See Observations <here>.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  -15 / 0
Ridgetop Wind Forecast (direction/mph): NE / 25-50
Snowfall (in): 0
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   ~ / ~  25 / NE
Max Wind Gust (mph) / Direction  ~ / ~  40 / NE
Temperature Min / Max (*F)  ~ / ~  5 / -13

Weather Forecast:    Sunny, cold, and stunningly beautiful Tuesday and Wednesday with brutal windchill over northerly outflow wind exposed terrain. Clouding up Wednesday evening with snow flurries intensifying Friday into a winter storm over the weekend depositing 1-2 feet of snow.

Additional Info & Media

SNOW HISTORY: Valdez 1/3 AM Thompson Pass 1/9 AM
24 Hour Snow / Water Equiv. 0”/ 0.43″ 0″ / 0″
Storm Snow /Water Equiv. (1/1-3) ” / ″ 30″ / 3.0″
Current Snow Depth 25″ 72″
January Snow / Water Equiv. 10″ /2.82 ″ 32″ / 3.1″
Total Winter Snowfall / Water Equiv. 74″ / 19.12” 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.
Pete Carter

Forecaster: Pete Carter