Monday-Thursday 3/12-3/15

Issued: Mon, Mar 12, 2018 at 8AM

Expires: Thu, Mar 15, 2018

Above 2,500ft Considerable

1,800 to 2,500ft Moderate

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

Monday Tuesday Wednesday
& Thursday

DANGER SCALE

 

WIND SLAB:
Elevation:   Above 2000′
Aspect:   Lee of ridges, gullies, ridgetops
Terrain:   Upper elevation terrain exposed to wind
Sensitivity:   Responsive
Distribution:   Specific
Likelihood (Human Triggered):   Likely
Size:   Small – Large
Danger Trend:   Increasing
Forecaster Confidence:    Good

STORM SNOW:
Elevation:
   All
Aspect:
   All  
Terrain: 
  30+ degrees steepness
Sensitivity:
   Responsive
Distribution:   
Widespread
Likelihood (Human Triggered): 
 Likely
Size:   
Small – Large
Danger Trend:
   Steady
Forecaster Confidence:
    Good

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: 

As much as two feet of new snowfall has accumulated over the past weekend. Strong northerly winds Sunday March 11 built windslabs.

Recent Avalanche Activity

No new observations. Limited visibility. Today, expect to see numerous windslab and storm snow avalanches that ran over the past 24 hours.
March 9: Two natural D1 windslab avalanches observed near miles 23 and 25 of the road corridor.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F): 20 / 28
Ridgetop Wind Forecast (direction/mph): NE /10-30
Snowfall (in):  4-8″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  7 / NE   30 / NE
Max Wind Gust (mph) / Direction  28 / NE  50 / NE
Temperature Min / Max (*F)  29 / 35  20 / 26

Weather Forecast:    Becoming sunny Monday. Storm Monday night with strong NE winds. Snowfall to continue through Wednesday with another foot accumulating. Overcast Thursday.

Additional Info & Media

SNOW HISTORY: Valdez 3/11 AM Thompson Pass 3/12 AM
24 Hour Snow / Water Equiv. 0”/ 0″ 10″ / 0.8″
Storm Snow /Water Equiv. (3/9-12) 6.3” / 0.41″ 14″ / 1.5″
Current Snow Depth 37″ 82″
March Snow / Water Equiv. 9.3″ / 0.55″ 16″ / 1.5″
Total Winter Snowfall / Water Equiv. 120.84″ / 24.92” 339″ / 34″
Snowload in Valdez 55 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.
Pete Carter

Forecaster: Pete Carter