Wednesday-Saturday 2/15-18

Issued: Wed, Feb 15, 2017 at 8AM

Expires: Sat, Feb 18, 2017

Storm cycle still in progress. If you choose to enter avalanche terrain, keep it low angle without exposure to steep slopes above or adjacent.

This Saturday, February 18, Kyle Sobek is leading a Backcountry & Avalanche Riding Safety Field Session. 9am-4pm. More details. Learn READY RIDER skills.

Above 2,500ft Considerable

1,800 to 2,500ft Considerable

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

WEDNESDAY THURSDAY FRIDAY & SATURDAY

DANGER SCALE

 

STORM SNOW:
Elevation: All
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Wide Spread
Likelihood (Human Triggered): Likely
Size: Small – Large
Danger Trend: Steady
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: 

With 3.62″ water equivalent in the last 72 hours, the snowpack is absorbing moisture and settling quickly. This storm is a classic crush and flush; old instabilities will not be a concern after this weather has run it’s stint. Give it time to adjust and re-set.

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: 

Observed Tuesday February 14:

  • wet avalanches to size 2.5 ran full track to sea level between Mineral Creek and Shoup Bay
  • wet avalanches to size 2 off Benzene Peak near Solomon
  • wet avalanches to size 2 fell off steeps of Keystone Canyon
  • wet avlaanches to size 2 ran into Snowslide Gulch above MP 15-16
  • poor visibility did not allow for further observations, but widespread activity below the rain line was expected

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  23 / 34
Ridgetop Wind Forecast (direction/mph): S / 7-14
Snowfall (in/water equivalent):  1-7″ / 0.48″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  Calm  12 / SE
Max Wind Gust (mph) / Direction  3 / WSW  38 / SE
Temperature Min / Max (*F)  34 / 42  29 / 31

Weather Forecast:  Even though the surface temperatures are above freezing at sea level, there is cool air aloft, causing continued snowfall above 800′ and snow/rain mix at lower elevations. Cooling this evening with snow possible through Saturday, accumulation of up to 9 more inches near sea level with 1/2″ water equivalent. Variable wind to 10mph.

Additional Info & Media

SNOW HISTORY: Valdez 2/15 AM Thompson Pass 2/15 AM
24 Hour Snow / Water Equiv. 0.0”/0.4″ rain 8″ /1″
Storm Snow /Water Equiv. (2/12-2/15) 29.8” /3.62″ 28″ /3.7″
Current Snow Depth 49″ 51″
February Snow / Water Equiv. 29.8″ /3.62″ 36″ / 4.4″
Total Winter Snowfall / Water Equiv. 208″ / 19.5” 275″ / 27″
Snowload in Valdez 62.4 lbs/sq. ft.

 

SNOWFALL for LAST 24 HRS at OTHER STATIONS (2/15 AM):
Nicks Valley at 4200 ft (in): 25″ HST  and 86″ HS
Upper Tsaina at 1750 ft (in): 2.7″ HSTW 2/13-15
Sugarloaf at 550 ft (in): 3.9″ HSTW 2/13-15
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.
Sarah Carter

Forecaster: Sarah Carter