Thursday-Sunday 2/16-19

Issued: Thu, Feb 16, 2017 at 8AM

Expires: Sun, Feb 19, 2017

Unreliable visibility and large amounts of new snow will make for strategic route planning with back-up plans.

Continuously evaluate the new snow in non-consequential terrain and proceed conservatively.

This Saturday, February 18, Kyle Sobek is leading a Backcountry & Avalanche Riding Safety Field Session. 9am-4pm. More details. Learn READY RIDER skills.

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




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

Elevation: Above 2000″
Aspect: Lee to SE wind
Terrain: Near ridges, gullies, rollovers
Sensitivity: Responsive
Distribution: Specific
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing
Forecaster Confidence: Good

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



Maritime (Coastal) Specific: 

With 3.62+” water equivalent in the last 4 days, the snowpack has absorbed large amounts of moisture and settled extensively. This storm has been a classic crush and flush topped off with a nice cold snow icing to the cake; old instabilities will not be a concern after this weather has run it’s stint. Give it time to adjust, cool, and solidify.

In the upper elevations, during windows of visibility, flagging of moving dry snow off the peaks in the port was seen. This means that new wind slam formation is of concern in the colder elevations above the rain line….estimated at ~3000′.

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

Maritime (Coastal) Specific: 

Observed Tuesday February 14:

  • wet avalanches to size 2.5 ran full track to sea level between Mineral Creek and Shoup Bay
  • wet avalanches to size 2 off Benzene Peak near Solomon
  • wet avalanches to size 2 fell off steeps of Keystone Canyon
  • wet avlaanches to size 2 ran into Snowslide Gulch above MP 15-16
  • poor visibility did not allow for further observations, but widespread activity below the rain line was expected

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  15 / 24
Ridgetop Wind Forecast (direction/mph): SE / 5-20
Snowfall (in/water equivalent):  3-4″ / 0.2″
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  5 / Var  20? / SE
Max Wind Gust (mph) / Direction  27 / W  43 / SE
Temperature Min / Max (*F)  27 / 37  19 / 30

Weather Forecast:  Skies have began to open and temperatures have dropped 10-20 plus degrees F over the last 24 hours, turning rain back to snow and locking up the water saturated snowpack. 7 more inches of snow fell around the port yesterday with random sucker holes that opened up throughout the day. Further interior, less precipiation, if any, fell as skies were more broken with variable skies. Look for shifty clouds today until this evening when a Bristol Bay low pressure system swings in more consistent moisture that could result in up to 6 more inches by Saturday morning. The weekend looks promising and clearing, with even further dropping of temperatures.

Additional Info & Media

SNOW HISTORY: Valdez 2/16 AM Thompson Pass 2/16 AM
24 Hour Snow / Water Equiv. 7.1”/0.5″ ?″ /?″
Storm Snow /Water Equiv. (2/12-2/16) 27.25” /3.74″ 28″ /3.7″
Current Snow Depth 53″ 51″
February Snow / Water Equiv. 36.9″ /4.12″ 36″ / 4.4″
Total Winter Snowfall / Water Equiv. 214.8″ /20.82” 275″ / 27″
Snowload in Valdez 78 lbs/sq. ft.


Nicks Valley at 4200 ft (in): 0?” / 25″ / ?”
Upper Tsaina at 1750 ft (in): 1?” / ?” / 2.7″
Sugarloaf at 550 ft (in): 7″/?”/ 3.9″
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>


  • 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 Maritime Forecasts.

Forecaster: Kevin Salys