Thursday-Sunday 3/16-19

Issued: Thu, Mar 16, 2017 at 8AM

Expires: Sun, Mar 19, 2017

While the wind and snow continue to blow, come enjoy the VAC Basecamp FREE classes that begin 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

THURSDAY FRIDAY SATURDAY & SUNDAY

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: 

Despite a dusting in the interior yesterday, 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 practically NO soft snow for skiing, snowboarding, or snowmachining in the Valdez region, yet some far off wind protected pockets have held some inconsistent soft snow/facets. 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: 

  • Recently reported from Mar 7: 2x D1 AS soft slabs (3500’ SW 20cm and 4000’ NE 15cm), long running dry loose and several collapses on low angle terrain.
  • Somewhat recent 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′

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  -2 / 6
Ridgetop Wind Forecast (direction/mph):  NE / 35-50
Snowfall (in/water equivalent):  0″ / 0″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  23 / SE  43 / NE
Max Wind Gust (mph) / Direction  42 / E  65 / NE
Temperature Min / Max (*F)  19 / 26  -1 / 6

Weather Forecast:   Yesterday supported high clouds around the port and interior while the pass had large pockets of pockets of blue during the afternoon. Currently, strong outflow winds out of the north are complemented by single digit overnight temperatures north of the pass and high teens in the port. Get out and enjoy the clear days until clouds move back in Satuday night and tease us with a flake or two until they clear out again Monday. These blocking highs north of us will just not budge, but at least the nearest low that is driving these horrible winds will dissipate and move east, making the next few days more appealing. Expect temperatures to rise with the arrival of the Sunday weather.

Additional Info & Media

SNOW HISTORY: Valdez 3/16 AM Thompson Pass 3/16 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 (3/16 AM)/STORM TOTAL (3/16)/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.

Forecaster: Kevin Salys