Wednesday-Saturday 4/11-4/14

Issued: Wed, Apr 11, 2018 at 7AM

Expires: Sat, Apr 14, 2018

Spring Fundraiser coming up this Friday April 13 at Tsaina Lodge. Door prizes! Silent auction!

Acoustic Avalanche and Jer Ber playing music.

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

Wednesday Thursday Friday & Saturday



Wet Avalanches:
Elevation:   Below 4000′
Aspect:   SE – S – SW
Terrain:   Southerly facing terrain >25 degrees exposed to sun
Sensitivity:   Non-reactive – Responsive as sun and warmer temperatures dominate
Distribution:   Specific
Likelihood (Human Triggered): Possible
Size:   Small 
Danger Trend:   Increasing with solar input and warmer temperatures
Forecaster Confidence:    Good

Wind Slab:
Elevation:   Above 3500′
Aspect:   Lee of ridges, gullies, ridge tops
Terrain:   Above 35< and exposed to wind
Sensitivity:   Stubborn – Responsive
Distribution:   Specific
Likelihood (Human Triggered): Possible
Size:   Small 
Danger Trend:   Decreasing
Forecaster Confidence:    Poor

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


SNOWPACK DISCUSSION:  Thompson Pass has daytime temperatures going above freezing at the mountain tops. Daytime warming is trapped by clouds with the greenhouse effect rapidly warming the snowpack.

These are the warmest days of the winter. The spring shed cycle is here. Don’t be in avalanche terrain when the daytime avalanches occur. Signs of wet snow avalanches include observations of new avalanches and seeing cornices and rocks fall. If you punch through to ground when on slushy snow and/ or the entire snowpack consists of slushy snow, question what’s holding it to the slope.

Most snow surface conditions are variable and range from wind scoured pencil hard sastrugi, sun effected melt/freeze, to decomposing unconsolidated particles.  Snow depths generally range from 30-300cm.

Test pits over the last three weeks have shown no signs of propagation.

See excellent observations <here>. We thank contributors.

Recent Avalanche Activity

No new observations.

Video of Winds from 3/22/18



Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F): 30 / 37
Ridgetop Wind Forecast (direction/mph): E / 15
Snowfall (in):  Trace”
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  2 / VAR   20 / E
Max Wind Gust (mph) / Direction  8 / E  30 / E
Temperature Min / Max (*F)  37 / 47  25 / 35

Weather Forecast:      One snowflake Wednesday. Clearing skies Thursday. Cloud cover again Friday and into the weekend with daytime temperatures at Thompson Pass into the 40’s F.

Additional Info & Media

SNOW HISTORY: Valdez 4/11 AM Thompson Pass 4/11 AM
24 Hour Snow / Water Equiv. 0”/ 0.0″ 0″ / 0.0″
Storm Snow /Water Equiv. (3/15-19) 19” / 0.41″ 40″ / 1.5″
Current Snow Depth 25″ 64″
April Snow / Water Equiv. 0″ / 0″ 0″ / 0″
Total Winter Snowfall / Water Equiv. 132.59″ / 27.2” 372″ / 36.6″
Snowload in Valdez 53 lbs/sq. ft.


SNOW DEPTH & WATER SURVEY (3/4/2018) Depth Snow Water Equivalent
Milepost 2.5 Valdez  32.2″  9″
Milepost 18 42″ 11″
Milepost 29 Worthington Flats 62.4″ 21.2″
Milepost 37 Tsaina River bridge 58.4″ 14.2″
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.
Pete Carter

Forecaster: Pete Carter