Sunday – Wednesday 3/19-22

Issued: Sun, Mar 19, 2017 at 8AM

Expires: Wed, Mar 22, 2017

Flat light will reduce your ability to see above and around you. Surfaces are hard and inconsistent, making injury from falls and crashes hurt more.

Join the VAC Basecamp FREE classes every day this week in the One Love Lot (MP 29.5). Check our Facebook page for more details! Today’s class: Introduction to Thompson Pass Terrain



Above 2,500ft Low

1,800 to 2,500ft Low

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




Elevation:   Above 2000′
Aspect:  Lee to northerly winds
Terrain:   Near ridges, gullies, rollovers
Sensitivity: Stubborn
Distribution:   Specific
Likelihood (Human Triggered): Unlikely
Size:   Small – Large
Danger Trend:   Decreasing
Forecaster Confidence:   Fair

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: 

Recent evaluation in the port area (<1000′) demonstrated that poor structure remains in the upper snowpack: primarily wind slab resting on weak sugar snow (old facets). Test results supported easy collapses and propagation of the knife-on-fist hard layer combo. This undesirable situation is a bit less concerning due to the breaking fracture character and friction/resistence within the thick, underlying weak layer that is bonding to the bottom of the wind slab. This is only where the wind slab can be found, for the majority of areas have been scoured down to the mid-February rain crust. Human triggered wind slab avalanches are unlikely, but steep, wind protected areas that retain the poor structure should be evaluated. You are most likely to trigger this slab where the snowpack is the thinnest. The last reported human triggered avalanche was March 11th.

There are limited soft snow options for skiing, snowboarding, or snowmachining in the Valdez region, yet some far off wind protected pockets have held some inconsistent soft snow/facets. Despite a dusting in the interior on Wednesday, Valdez has not seen significant snowfall for one month. 13 of the last 16 days had 50 mph wind gusts, approaching 100 mph at the beginning of this month. This wind cycle has completely scoured and stripped all peaks and ridges of their snow. Glacial ice has been exposed in areas normally visible mid summer. Entrances to many “normal” ski runs are bare rock.

Rain Crust from mid Feb.

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: 

  • March 7 : report of two human triggered size D1 soft slabs (20cm deep on a SW aspect at 3500′ and 15cm deep on a NE aspect at 4000′). Some human triggered dry loose activity to size D1.5. With several collapses felt on low angle terrain.
  • March 2/3 : report of windslabs to size 2 released to ground near the 3000′ elevation on aspects lee to north wind.

Wind slab to ground west of Meteorite. NE aspect at ~3000′

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  -2 / 15
Ridgetop Wind Forecast (direction/mph):  NE / 24-40
Snowfall (in/water equivalent):  1-4″ / 0.27″
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  9 / NE  33 / NE
Max Wind Gust (mph) / Direction  23 / NE  35 / NE
Temperature Min / Max (*F)  14 / 23  -5 / 4

Weather Forecast:   Grey bird today as a weak low pressure moves over. Snow flurries adding up to a couple of inches by Monday morning. With the ridge of high pressure over the Bering Sea blocking any significant atmospheric shift, no significant snowfall is expected for another week or more. Temperatures in the single digits F will continue near Thompson Pass and further interior. Northeast wind to 40 mph. Expect the wind to abate as flurries fly, but pick up again Monday.

Additional Info & Media

SNOW HISTORY: Valdez 3/18 AM Thompson Pass 3/19 AM
24 Hour Snow / Water Equiv.  0”/0″ 0.2″ /0.01″
Storm Snow /Water Equiv. (2/23)  0″ /0″ 2″ /0.1″
Current Snow Depth 37″ 38″
March Snow / Water Equiv. 0″ /0″ 0.2″ / 0.01″
Total Winter Snowfall / Water Equiv. 222.8″ /20.9” 283″ / 27.7″
Snowload in Valdez ~ lbs/sq. ft.


Nicks Valley at 4200 ft (in): 0″ / 0″ / 0″
Upper Tsaina at 1750 ft (in): 0″ / 0″ / 0″
Sugarloaf at 550 ft (in): 0″/ 0″ / 0″
SNOW DEPTH & WATER SURVEY (2/28/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  41.8″  12″
Milepost 18 42.7″ 11.5″
Milepost 29 Worthington Flats 63.6″ 18.6″
Milepost 37 Tsaina River bridge 49.3″ 12.5″
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.
Sarah Carter

Forecaster: Sarah Carter