Monday-Thursday 2/13-16

Issued: Mon, Feb 13, 2017 at 8AM

Expires: Thu, Feb 16, 2017

The avalanche hazard is quickly rising as storm snow stacks up on a variety of weak or firm surfaces combined with the possible complexity of rain on dry snow.

Travel in avalanche terrain is NOT recommended.

Monitor the bonding of new to old and for density variations in the storm slab that could be the weak link.

Rain on new snow can quickly destabilize the structure and lead to avalanches.

Do not linger in or below avalanche terrain and expose only one at a time when necessary.

Above 2,500ft High

1,800 to 2,500ft High

Below 1,800ft Considerable

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

STORM SNOW:

Elevation: All
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Wide Spread
Likelihood (Human Triggered): Likely
Size: Small – Large
Danger Trend: Increasing
Forecaster Confidence: Good

WET AVALANCHES:

Elevation: All
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Wide Spread with rain on snow
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing
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:

Maritime (Coastal) Specific: 

More snow has accumulated in the maritime zone than up on Thompson Pass, with 20 inches of new in town early Monday morning. Given expected rising temperatures above freezing up to 3000′, rain on new snow in the lower elevations could quickly destabilize steep slopes and lead to widespread avalanche activity. This could result in both loose wet and wet slab activity.

Find more photos and observations at the bottom of the page. Sharing your observations creates an informed community that everyone benefits from at some point.

Recent Avalanche Activity

Maritime (Coastal) Specific: 

  • No new observations reported.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  25 / 34
Ridgetop Wind Forecast (direction/mph): SE / 10-40
Snowfall (in):  8-18
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   5 / NE  23 / Var
Max Wind Gust (mph) / Direction  13 / E  37 / ESE
Temperature Min / Max (*F)  18 / 29  6 / 28

Weather Forecast:  As snow began to trickled in yesterday, it has stacked up 20 inches of new snow in town and only half that up on Thompson Pass (likely affected by winds). It looks that the the low pressure system to the west will continue to channel warm air and water at us until mid-day Tuesday. The main question is how warm will it get and how high will the rain line rise to today and tonight. Even though things seem better than previously forecasted, above freezing temperatures could hit 3000′, bringing rain on snow up to Thompson Pass.

Additional Info & Media

SNOW HISTORY: Valdez 2/13 AM Thompson Pass 2/13 AM
24 Hour Snow / Water Equiv. 20.5”/1.1″ 10″ /0.8″
Storm Snow /Water Equiv. (2/12-13) 20.5” /1.1″ 10″ /0.8″
Current Snow Depth 60.5″ 42″
February Snow / Water Equiv. 26.5″ /1.4″ 18″ / 1.2″
Total Winter Snowfall / Water Equiv. 204″ / 17.3” 255″ / 23.9″
Snowload in Valdez 68 lbs/sq. ft.

 

SNOWFALL for LAST 24 HRS at OTHER STATIONS (2/13 AM):
Nicks Valley at 4200 ft (in): 9″
Upper Tsaina at 1750 ft (in): 10″
Sugarloaf at 550 ft (in): 16″
SNOW DEPTH & WATER SURVEY (2/1/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  41.5″  9.8″
Milepost 18 43.9″ 9.5″
Milepost 29 Worthington Flats 61.5″ 16″
Milepost 37 Tsaina River bridge 42.1″ 9.3″
This survey is done the first week of each month.

Weather Quicklinks:

  • NWS forecast for Northeast Prince William Sound <here>
  • NOAA NWS spot forecast for Thompson Pass <here>
  • Thompson Pass RWIS weather station <here>
  • MP 30 Nicks (Happy) Valley weather station at 4200 feet <here> (scroll to Nicks Valley)
  • Valdez Glacier UAF weather station at 6600 feet <data here> <map here>
  • Further weather resources <here>

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 Maritime Forecasts.

Forecaster: Kevin Salys