Wednesday-Saturday 3/15-18

Issued: Wed, Mar 15, 2017 at 8AM

Expires: Sat, Mar 18, 2017

VAC Basecamp’s first round of FREE classes begins Friday in the One Love Lot (MP 29.5), check our Facebook page for more details!

Citizen Science Opportunity in Thompson Pass: March 18, 2017: 9:30am at DOT Camp (MP 27).  Join VAC forecasters, staff, and volunteers in measuring the snow cover throughout Thompson Pass. Learn more at www.nasacso.org or at the Fat Mermaid March 16 & 17 @ 5:30pm.

 

Above 2,500ft Low

1,800 to 2,500ft Low

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

WEDNESDAY THURSDAY FRIDAY &
SATURDAY

DANGER SCALE

 

WIND SLAB:
Elevation:   Above 2000′
Aspect:  Lee to northerly winds
Terrain:   Near ridges, gullies, rollovers
Sensitivity: Stubborn
Distribution:   Specific
Likelihood (Human Triggered): Unlikely
Size:   Small – Large
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

AVALANCHE PROBLEM TOOLBOX <here>

SNOWPACK DISCUSSION:

Maritime (Coastal) Specific: 

Valdez has not seen significant snowfall for one month as of today. 13 of the last 16 days had 50 mph wind gusts, approaching 100 mph at the beginning of this month. This wind cycle has completely scoured and stripped all peaks and ridges of their snow. Glacial ice has been exposed in areas normally visible mid summer. Entrances to, “Normal” ski runs aren’t even fathomable. There is virtually NO soft snow for skiing, snowboarding, or snowmachining in the entire Valdez region. Human triggered avalanches are still possible. If you do decide to recreate in the mountains today, the snow will most likely be hard and sketchy. Skiers, know self arrest skills. Snowmachiners, be prepared to total your sled.  In regards to avalanches ask your self, “what lies underneath this hard snow?” If it’s sugar (facets), which it probably is, it can avalanche. You are most likely to trigger this slab where the snowpack is the thinnest. The last reported human triggered avalanche was March 11th.

 

Steep, low elevation southerlies melting out.

Thompson Pass gap winds still scouring into the snowpack.

Rain Crust from mid Feb.

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 recent avalanche activity seen, but some recently seen wind slabs (likely occured during Mar. 2-3 wind event) had scoured/released to ground near the 3000′ elevation on varying aspects.

Wind slab to ground west of Meteorite. NE aspect at ~3000′

Scouring/releases to ground near East Peak. SE aspect at ~3500′

  • Mar. 2: More natural wind slabs to size 2 pulling off steep ridgelines and rollovers in terrain exposed to strong northerly outflow wind.

Wind slab releases above the airport

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  -7 / -1
Ridgetop Wind Forecast (direction/mph):  NE / 25-55
Snowfall (in/water equivalent):  1″ / 0.07″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  12 / E  42 / NE
Max Wind Gust (mph) / Direction  44 / E  65 / NE
Temperature Min / Max (*F)  20 / 25  0 / 7

Weather Forecast:   COLD temperatures and strong winds have returned to Valdez and the surrounding region. A light dusting is possible today with no real significant accumulation (1”). Expect cloud cover to be mostly overcast with bits of light poking through. A couple snowflakes will fall here and there throughout this week as a low pressure system is building in the gulf. The first real snow opportunity in one month is possible this Sunday/Monday.

Additional Info & Media

SNOW HISTORY: Valdez 3/15 AM Thompson Pass 3/15 AM
24 Hour Snow / Water Equiv.  0”/0″ 0″ /0″
Storm Snow /Water Equiv. (2/23)  0″ /0″ 2″ /0.1″
Current Snow Depth 37″ 39″
March Snow / Water Equiv. 0″ /0″ 0″ / 0″
Total Winter Snowfall / Water Equiv. 222.8″ /20.9” 283″ / 27.7″
Snowload in Valdez ~ lbs/sq. ft.

 

SNOWFALL at OTHER STATIONS:
LAST 24 HRS (3/10 AM)/STORM TOTAL (3/10)/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″/ 0″ / 0″
SNOW DEPTH & WATER SURVEY (2/28/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  41.8″  12″
Milepost 18 42.7″ 11.5″
Milepost 29 Worthington Flats 63.6″ 18.6″
Milepost 37 Tsaina River bridge 49.3″ 12.5″
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.
Kyle Sobek

Forecaster: Kyle Sobek