Tuesday-Friday 4/10-4/13

Issued: Tue, Apr 10, 2018 at 7AM

Expires: Thu, Apr 12, 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

Tuesday Wednesday Thursday & Friday



Wet Avalanches:
Elevation:   Below 3000′
Aspect:   SE – S – SW
Terrain:   Southerly facing terrain above 25< and 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:    Fair

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:    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


SNOWPACK DISCUSSION:  Thompson Pass has had very warm temperatures recently, reaching above 32°f at 5000′. Cloud cover has rolled in from the coast acting like a blanket locking all the warm air in over night. Thompson Pass did not receive a hard freeze last night due to cloud cover. We are experiencing some of the warmest days of the winter and the spring shed cycle is upon us. DO NOT be in the mountains when they start to shed. It’s amazing how quick this shed cycle happens. Easy sings of potential wetslab avalenhes are: Punching through to ground while standing/walking on slushy snow, cornice/rock fall, the entire snowpack consisting of slushy snow, fresh natural wet avalanches near you-GET OUT IF YOU ARE EXPERIENCING ANY OF THESE SINGS.

Saturday, April 7, the area around Thompson pass above 3000′ experienced several hours of NE winds in the upper 40mph range which transported unconsolidated snow.  Some of that snow sublimated, while the remainder created small wind slab in isolated areas in the lee of ridges, gullies, and ridge tops.

The advisory area experienced a significant wind event March 19-22 and minimal snow since then.  April 5 produced ~6″ of snow in areas above 3500′.  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.

Check out our public observations and contribute to them!  Thanks!



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): 32 / 35
Ridgetop Wind Forecast (direction/mph): Variable / 10
Snowfall (in):  Trace”
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  calm / VAR   10 / NE
Max Wind Gust (mph) / Direction  7 / ESE  23 / NE
Temperature Min / Max (*F)  36 / 47  30 / 35

Weather Forecast:   Mostly cloudy with light winds. At 3000′ the temperatures will be above freezing during the day, and may not reach below freezing tonight. Lower elevation temperatures will reach above freezing during the day, in the upper 40*F (5-9*C) range and will not be freezing at night. Slight chance of precipitation today with rain in town and a dusting on the pass.

Additional Info & Media

SNOW HISTORY: Valdez 4/10 AM Thompson Pass 4/10 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 29″ 56″
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: http://www.avalancheforecasts.com/

Posted in Continental Forecasts, Intermountain Forecasts, Maritime Forecasts.
Kyle Sobek

Forecaster: Kyle Sobek