Thursday-Sunday April 6-9

Issued: Thu, Apr 06, 2017 at 9AM

Expires: Sun, Apr 09, 2017

Arctic Man 2017
Always wear a beacon, shovel and probe while traveling in the mountains. Sled causalities are likely with low snow conditions.

Friday April 7 11am-1pm to practice your Avalanche Rescue Skills. Stop by the Avalanche information kiosk; we’re across from the showers on the corner of Racer’s Row, not too far from the beer tent.

Above 4,000ft Low

3,000 to 4,000ft Low

Below 3,000ft Low

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

THURSDAY FRIDAY SATURDAY & SUNDAY

DANGER SCALE

 

WIND SLAB OVER PERSISTENT WEAK LAYER:
Elevation:   Above 3000″
Aspect:  Lee to north wind
Terrain:   Near ridges, gully walls, rollovers
Sensitivity:   Stubborn
Distribution:   Specific
Likelihood (Human Triggered):   Unlikely
Size:   Small – Large
Danger Trend:   Steady
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

AVALANCHE PROBLEM TOOLBOX <here>

North side of Courage Mountain April 3, 2017   Photo: Conrad Chapman

SNOWPACK DISCUSSION: The entire Eastern Alaska Range consists of very thin snow coverage. On average the snowpack is 20 inches deep surrounding the Summit Lake area. Only about 2 inches fell in the Arctic Man Parking Lot Saturday night. The lack of snow is the main factor in the, “Low” danger rating. Even though the danger is low, certain slopes still have a potential of releasing. These slopes include: wind loaded slopes, slopes high in elevation, and sun warmed slopes (especially if the three are combined). The warm sun is starting to become a concern, especially if the snow does not freeze overnight.

evidence of old avalanche activity in upper elevations Photo: Sarah Carter

Video showing layers of hard cohesive snow over weak punchy facets

 

 

Recent Avalanche Activity

Tuesday a snowmachiner triggered a small pocket of windslab on a steep sun-warmed slope. The crown was 6″- 2′ thick and released just under the ridge. The avalanche was a size 1, not large enough to bury & kill a person.

Recent Weather

Mostly sunny today, with a possibility of clouds rolling in later in the evening. The high will reach above freezing in the warmth of the afternoon sun. The weather is going to continue to warm through out the week. This warming trend will increase the likelihood of a wet avalanche, especially if the temperatures do no drop below freezing over night.

Additional Info & Media

SNOW HISTORY: Valdez 2/24 AM Thompson Pass 2/24 AM
24 Hour Snow / Water Equiv. <0″/0″ 0″ /0″
Storm Snow /Water Equiv. (2/22-2/23) 0.6” /0.05″ 1″ /0.1″
Current Snow Depth 48″ 49″
February Snow / Water Equiv. 44.9″ /5″ 43″ / 5.1″
Total Winter Snowfall / Water Equiv. 222.8″ /20.9” 282″ / 27.7″
Snowload in Valdez ~ lbs/sq. ft.

 

SNOWFALL at OTHER STATIONS:
LAST 24 HRS (2/24 AM)/STORM TOTAL (2/22-23)/STORM WATER EQUIV.:
Nicks Valley at 4200 ft (in): 0″ / 0″ / 0″
Upper Tsaina at 1750 ft (in): 0″ / 0″ / 0″
Sugarloaf at 550 ft (in): 0″/ 1″ / 0.1″
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 EARAC Forecasts.
Kyle Sobek

Forecaster: Kyle Sobek