Sunday-Wednesday 4/8-4/11

Issued: Sun, Apr 08, 2018 at 8AM

Expires: Wed, Apr 11, 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

Sunday Monday Tuesday & Wednesday

1-low 1-low

DANGER SCALE

 

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

AVALANCHE PROBLEM SCALE DESCRIPTORS:
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

LIST OF AVALANCHE PROBLEMS <here>

SNOWPACK DISCUSSION:      The relatively warm daytime temperatures and consistent solar radiation is causing southeast, south, and southwest aspects to thaw.  Rapid warming is possible today below 3000′, and unlikely above 3000′.  Rapid thawing can quickly change the stability of the snowpack and lead to avalanches and cornice fall. It’s time to get out of avalanche terrain if you see or experience signs of rapid warming such as: temperatures above freezing, roller balls or pinwheels in the snow, cornice fall, wet avalanches, or heavy/sticky snowpack.

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): 29 / 34
Ridgetop Wind Forecast (direction/mph): E / 1-13
Snowfall (in):  0”
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  8 / VAR   29 / NE
Max Wind Gust (mph) / Direction  25 / ESE  49 / NE
Temperature Min / Max (*F)  36 / 52  23 / 33

Weather Forecast:   Mostly sunny with light winds. In the alpine, temperatures will be below or near freezing during the day and around 20*F (-6*C) in the evening.  Lower elevation temperatures will reach above freezing during the day, in the upper 40*F (5-9*C) range.  Chance of precipitation possible early next week.

Additional Info & Media

SNOW HISTORY: Valdez 4/8 AM Thompson Pass 4/8 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:

 

SNOW CLIMATE ZONES:

  • 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

thompson-pass-ski-runs

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

climate-zones-topoclimate-zones-satellitegoogle-earth1

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.

Forecaster: Ryan Van Luit