Saturday-Tuesday 3/31-4/3

Issued: Sat, Mar 31, 2018 at 8AM

Expires: Tue, Apr 03, 2018

Bring your families and kids out to Beacons & Eggs today March 31 10am-noon. Salmon Berry Ski Hill at Mile 6. Learn and practice backcountry safety skills with some Easter fun!

Above 2,500ft Low

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

Saturday Sunday Monday & Tuesday
2-moderate 3-considerable 2-moderate

DANGER SCALE

 

Wet Avalanches:
Elevation:   Below 3000′ (this elevation may increase if the temperatures rise above prediction)
Aspect:   All, especially SE-S-W
Terrain:   Slopes above 25<
Sensitivity:   Stubborn (Potentially increasing to Touchy if the temperatures and/or solar input reach above freezing)
Distribution:   Widespread
Likelihood (Human Triggered):   Possible with potential to increase to likely as temperatures increase
Size:   Small – Large
Danger Trend:   Increasing
Forecaster Confidence:    Fair

Cornice fall:
Elevation:   Below 3000′ (this elevation may increase if the temperatures rise above prediction)
Aspect:   All, especially E-S-W
Terrain:   Any ridges or gullies with visible cornice
Sensitivity:   Stubborn
Distribution:   Widespread
Likelihood (Human Triggered):   Possible – Likely
Size:   Small 
Danger Trend:   Increasing
Forecaster Confidence:    Fair

Wind Slab:
Elevation:   Above 4000′
Aspect:   Lee of ridges, gullies, ridge-tops
Terrain:   Northerly facing terrain above 35< and exposed to winds
Sensitivity:   Stubborn
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 likely to occur today below 3000′, and possible above that.  Rapid warming can quickly change the stability of the snowpack and lead to avalanches and cornice fall. Because the surface snow is relatively dense, it’s less susceptible to rapidly thaw compared to snow from a fresh storm.  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 collapse, wet avalanches, or heavy/sticky snowpack.

The advisory area experienced a significant wind event March 19-22.  These northerly winds scoured loose snow leaving a pencil hard wind layer on the surface. Gullies were filled in with deep, smooth wind slab and snow surface textures vary from sastrugi to patches of softer wind and sun effected snow.  Since the wind event, the temperatures have remained mostly below or near freezing in the alpine.  The wind slabs have been settling and creating stronger bonds.

Test pits over the last 10 days have shown no signs of propagation.

Check out our public observations

 

Recent Avalanche Activity

No recent activity observed or reported.

Video of Winds from 3/22/18

 

 

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F): 18 / 25
Ridgetop Wind Forecast (direction/mph): NE / 10-25
Snowfall (in):  0”
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  4 / Variable   21 / ENE
Max Wind Gust (mph) / Direction  18 / SE  31 / ENE
Temperature Min / Max (*F)  34 / 42  15 / 25

Weather Forecast:   Sunny with light to moderate winds. In the alpine, temperatures will most likely stay below freezing during the day and around 20*F (-6*C) in the evening.  Lower elevation temperatures will be above freezing during the day (into the 40’s*F (5-9*C)) and drop below freezing at night.  No snow in the forecast.

Additional Info & Media

SNOW HISTORY: Valdez 3/31 AM Thompson Pass 3/31 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 31″ 60″
March Snow / Water Equiv. 20.5″ / 2.61″ 49″ / 3.6″
Total Winter Snowfall / Water Equiv. 132.59″ / 27.2” 372″ / 36.6″
Snowload in Valdez 45 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