December 18, 2017

Issued: Mon, Dec 18, 2017 at 8AM

Expires: Thu, Dec 21, 2017

Avoid features like gully walls and ridge tops that are actively being loaded by northeast wind. Cautious route finding and conservative decision making essential. Re-group out of harm’s way.

Put your avalanche eyeballs on and look for recent avalanche activity from the Dec.2-14 storm event. Please share your obs.

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

Dry surface snow has been drifted in the last 24 hours by light to moderate NE wind. Expect fresh windslab to 6-12″. Deeper pockets lee of ridges and gullies could be sensitive to human trigger.

Dec.2-14 storm snow totaled 110″. Producing snowpack depths 5-6 feet at Thompson Pass with depth increasing with elevation. On Little Girls at about 3500′, Dec.15, an observer reported finding an average snowpack depth of 8-9′ with 4-5′ of that being December’s storm snow.

Recent Avalanche Activity

Numerous (mostly loose snow?) avalanches to size 2.5 ran during the storm(s) December 12-15. Both crown lines and deposits have been covered with subsequent snowfall.

Moist snow avalanches to size 2.5 observed Monday December 11 to the valley floor at Milepost 40 off Wilbur’s.

Numerous avalanches to size 3 ran to the valley floors across the region Wednesday December 6 and Friday December 8.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):   14/26
Ridgetop Wind Forecast (direction/mph):  NE/10-25
Snowfall (in/water equivalent): trace” /0.1″
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   2 /variable 12 /ENE
Max Wind Gust (mph) / Direction   4 /NE-NNE  26 /ENE
Temperature Min / Max (*F) 28 /33 18/26

Weather Forecast:

Monday clear skies. Cooler temps warming by Tuesday with precip. amounts to 1″ water by Wednesday. While skies are clear, light to moderate NE wind shifting to SE as next low pressure moves in. Expect over a foot of new snow by Wednesday.

Additional Info & Media


SNOW HISTORY: Valdez 12/18 AM Thompson Pass 12/18 AM
24 Hour Snow / Water Equiv. 1”/ 0.06″ 2″ /0.1″
Storm Snow /Water Equiv. [12/10-18]  3.5″ /3.5″snow+rain 46″ /6.4″
Current Snow Depth 16″ 60″
December Snow / Water Equiv. 38″ /13.17″ 132″ / 17.6″
Total Winter Snowfall / Water Equiv. 51″ /15.42” 197″ / 23.1″
Snowload in Valdez 45 lbs/sq. ft.


Nicks Valley at 4200 ft (in): 0″ / ?” / ?”
Upper Tsaina at 1750 ft (in): 0″ / 6″ /1.9″
Sugarloaf at 550 ft (in): ?”/ ?” /3.8″
SNOW DEPTH & WATER SURVEY (12/2017) 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:


  • 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


Interactive Map of Valdez Forecast Areas w/ Many Resource Layers (Trevor Grams)


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:

Posted in Continental Forecasts, Intermountain Forecasts, Maritime Forecasts, VAC Forecasts.
Sarah Carter

Forecaster: Sarah Carter