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Valdez

Wednesday-Saturday 1/18-1/21

Wed, Jan 18, 2017 at 8AM

Expires: Sat, Jan 21, 2017

Choose lower angle slopes to play on today. Pay attention to windlips and rollovers to know where the windslab is building. Gullies will most likely be crossloaded, gathering deep slab that could get moving fast in steep terrain.

Above 2,500ft Considerable

1,800 to 2,500ft Moderate

Below 1,800ft Moderate

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 1800′
Aspect: South and west, but all exposed to wind have been loaded in the last week
Terrain:
Slopes steeper than 30 degrees, loaded by NE wind
Sensitivity:
 Responsive
Distribution:
 
Specific
Likelihood (Human Triggered): 
Likely
Size:
 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

LIST OF AVALANCHE PROBLEMS <here>

SNOWPACK DISCUSSION: Coverage doesn’t look much better than before the Jan.13-17 storm that laid down 54 inches of snow. Both south and north wind has stripped and redistributed what fell. Now, strong northeast wind is again wrecking havoc: expect windslab depths to 3 feet or more on lee features. The cold temperatures, near or below zero F, at Thompson Pass and inland will decrease the bonding strength of fresh windslab and storm snow to old surfaces.

In wind protected areas, the storm snow is settling and has formed a soft slab. Skiers reported large whumphs near the Worthington Glacier, reminding us we cannot fully trust this snowpack yet, especially inland of Thompson Pass. Structurally the weak sugar snow lower in the pack is precariously holding up top heavy mid and upper slab layers.

The spooky large avalanche west of Milepost 33, south aspect about 4000′, is evidence that increased load can trigger and cause a step down to deep old presistent weak layers.

Find more photos and observations at the bottom of the page. Sharing your observations helps others make informed decisions.

Recent Avalanche Activity

With a few short windows of visibility Tuesday, surprisingly not much avalanche activity was observed. The increase in temperature during the storm seemed to glue on what wasn’t blown away. Please share what you see.

coastal-zone-iconMaritime (Coastal):

intermountain-zone-iconInter-Mountain (Transitional):  

interior-zone-iconContinental (Interior):

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  -12 / 3
Ridgetop Wind Forecast (direction/mph): NE / 12-42
Snowfall (in):  0″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction   10/ var  30 / var
Max Wind Gust (mph) / Direction  18 / NE  55 / NE
Temperature Min / Max (*F)  18 / 24  -2 / 12

Weather Forecast: Windy and cold Wednesday and Thursday. With a mass of cold arctic air, north outflow wind is ramping up, only to die down by Friday when another low pressure will move in with clouds. Expect flurries by Saturday.

Additional Info & Media

SNOW HISTORY: Valdez 1/18 AM Thompson Pass 1/18 AM
24 Hour Snow / Water Equiv. trace” /0.03” 1″ /0.01″
Storm Snow /Water Equiv. (1/13-1/17) 46.41” /3.22″ 54″ /4.2″
Current Snow Depth 44.07″ 36″ (wind scoured)
January Snow / Water Equiv. 46.41″ /3.22″ 54″ / 4.2″
Total Winter Snowfall / Water Equiv. 44.85″ / 13.04” 197″ / 18.6″
Snowload in Valdez 27.56 lbs/sq. ft.

img_20161228_130954img_20161228_130730

Photos of our new Nicks Valley Weather Station Python to the east, Berlin Wall to the west.

SNOWFALL for LAST 24 HRS at OTHER STATIONS:
Nicks Valley at 4200 ft (in): ~5″
Upper Tsaina at 1750 ft (in): ~3″
Sugarloaf at 550 ft (in): ~3″
SNOW DEPTH & WATER SURVEY (1/3/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  22.7″  4.7″
Milepost 18 27.9″ 5.9″
Milepost 29 Worthington Flats 44″ 9.9″
Milepost 37 Tsaina River bridge 33.8″ 5.6″
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 VAC Forecasts.

Observations

Tell us what you're seeing out there.

41 Comments on Valdez

Sarah Carter
Sarah_Carter said : Report Subscribe yesterday

WINDSLAB! During the storm at about 11am January 16 the wind shifted from northeast to southeast. In 20 minutes the temperature rose 14 degrees F (from 8 to 23F). Wind had been strong from the northeast (27 Mile RWIS at the gap had gusts to 47mph from northeast, average for more than 6 hours of more than 20mph that morning). Then it switched to southeast and later, southwest with gusts to 40mph. This leaves the 54" of storm snow distributed as wind slab in wind exposed areas. DEEP drifting over questionable layers and bed surfaces. The RWIS anemometer did get rimed or stopped recording for a few hours at a time during the storm, but is now up again. http://roadweather.alaska.gov/iways/roadweather/forms/AtmoSum.html?areaId=3&perspectiveId=1&siteId=26&startDate=01172017&interval=1&action=Update

  • 16/01/2017
KSalys said : Report Subscribe 4 days ago

1230-430PM: Gusty and snow drifting onto the road outflows in Keystone Canyon and at/below the Thompson Pass Gap. Mixing SE winds just on the Maritime side of the pass. Very cold still 0*F at Nicks and the Tsaina River flats at MP 33. Snow seems to sticking well, but new snow has not consolidated much....very weak. On the north side of the pass, A slightly less dense layer of new snow was failing just above the old snow interface...allowing the slightly denser snow above to slide off in steep, unsupported sections (see profile attached). Snow was more consistent on the south side (maritime) and just failing mid storm snow. Much warmer on the maritime side: 22*F. Snowfall rate pick up as the afternoon passed....S-1 to S2.

  • 13/01/2017
Sarah Carter
Sarah Carter said : Report Subscribe 2 weeks ago

Crudbusters -17C/1F at trailhead, broken cloud, wind increased as we were out. Gusty strong northeast wind moving snow made us turn around. Recycled powder with little base below treeline. Still a lot of bush to bash. Wind hammered surfaces above treeline. Snow depth at 2600' was 75cm/30".

  • 05/01/2017
KSalys said : Report Subscribe a week ago

Exploration up Mineral Creek revealed the extent of the scouring and stripping back of the snow in our region from the recent extreme wind event. Snow was peeled down to rocks and old tracks (pre-Christmas) that were elevated out of the present surfaces. Alders were starting to reappear and pop free from the weight of snow. The present surfaces are extemely firm (1 finger to knife hard) and uneven with sastrugi. Evaluated layers seem welded together up to 3500' with only a few recent-looking, D1-D2 slabs that pulled out of steep, unsupported terrain. Two of these slabs release at the ground/rock level. There could have been more recent avlanche activity, but the wind affects could have easily masked and aged debris to seem old from previous storm events. No settlement or whumphing experienced. Temperatures were comfortable (40*F in town) out of the wind until nearing ridgetops where gusts were strong with old, large snow crystal transport stinging the face.

  • 07/01/2017
chance said : Report Subscribe 2 weeks ago

Road run. Saw two human triggered size 2 wind slab avalanches from yesterday. The wind was still transporting snow this afternoon. I experienced my first whumph in the flats on undisturbed snow. Temperature inversion 10° at bottom 20° at top.

  • 01/01/2017

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