Tuesday-Friday 1/16-1/19

Issued: Tue, Jan 16, 2018 at 8AM

Expires: Fri, Jan 19, 2018

Valdez, Thompson Pass, and the Copper Basin have received 2-4 feet of new snow since January 14. Give this new snow 2-3 days to settle before approaching avalanche terrain (30-45 degree slopes). Be on the lookout for natural avalanches. If you see natural avalanches, stay far away from slopes of similar aspect/elevation.  The danger will increase with wind transport.

Above 2,500ft Considerable

1,800 to 2,500ft Moderate

Below 1,800ft Moderate

Degrees of Avalanche Danger ?

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

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

TUESDAY WEDNESDAY THURSDA
Y& FRIDAY

DANGER SCALE

 

 

LOOSE SNOW:
Elevation:   Above 1800′
Aspect:   All
Terrain:   35+ degrees steepness
Sensitivity:   Responsive
Distribution:   Widespread
Likelihood (Human Triggered):   Likely
Size:   Small – Large
Danger Trend:   Steady
Forecaster Confidence:   Good

WIND SLAB:
Elevation:
   Above 2000′
Aspect:  
 Lee of ridges, gullies, ridgetops
Terrain: 
  All terrain exposed to wind
Sensitivity:
   Responsive
Distribution:   
Specific
Likelihood (Human Triggered):   
Likely
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:  A  good Ol’ Copper Whopper ran its course on the Eastern Chugach this weekend. Storm totals range from 18’’ in Kenny Lake/Chitina to 36’’ at 46 mile/Thompson Pass. This snow came in fairly “blower” but peaked out with heavier characteristics during the brunt of the storm. As with any big storm expect wind slabs and storm snow to be major concern. Give this new snow 2-3 days to settle before exposing your self to avalanche terrain. Previous to this storm there were concerns of a persistent weak layer about 1-2’ under the snow surface. This persistent weak layer is now buried 3-4’ down, be on the look out for natural avalanche activity on this old layer. If you see natural avalanches on this layer, use extreme caution on slopes of similar aspect/elevation.

Recent Avalanche Activity

A few natural avalanches to size D2 where observed from town to elevations up to 4000′.  No additional reports of natural or human triggered avalanches further interior.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  21/ 31
Ridgetop Wind Forecast (direction/mph): E / 7-31
Snowfall (in): 0-4
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   2 / N  22 / ENE
Max Wind Gust (mph) / Direction  12 / N  30 / ENE
Temperature Min / Max (*F)  34 / 43  27 / 35

Weather Forecast:  Early this week temperatures near the coast will remain above freezing. As one travels towards Thompson Pass and the Interior Region expect temperatures to remain below freezing. Snowfall will be spotty throughout the week, but there is a chance of northerly air prevailing and sunnier skies this Thursday/Friday. The Jet Stream seems to be changing directions towards Washington State, but as always mother nature will keep us on our toes.

Additional Info & Media

SNOW HISTORY: Valdez 1/14 AM Thompson Pass 1/14 AM
24 Hour Snow / Water Equiv. ~”/ ~” ~″ / ~″
Storm Snow /Water Equiv. (1/13-present) rain” / 0.45″ 12″ / 0.45″
Current Snow Depth 25″ 78″
January Snow / Water Equiv. 13.25″ / 4.19 ″ 44″ / 3.55″
Total Winter Snowfall / Water Equiv. 77.1″ / 20.49” 252″ / 27.75″
Snowload in Valdez 45 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): rain” /rain” / 0.4″
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.
Kyle Sobek

Forecaster: Kyle Sobek