Light winds around Thompson pass this morning are deceiving. Moderate wind during the snow storm yesterday transported significant amounts of low density snow to the lee of gullies and ridges. Cautious route finding and conservative decision making essential. Re-group out of harm’s way.
Above 2,500ft High
1,800 to 2,500ft Considerable
Below 1,800ft Moderate
Degrees of Avalanche Danger ?
Yesterday’s storm included lower density snow and moderate winds – expect windslab on lee features. Pockets lee of ridges and gullies are likely still sensitive to human trigger. Expect to find cross loaded features and large wind pillows.
With time and settlement, expect the storm snow to become increasingly cohesive.
We have no new field observations since the storm began yesterday but expect to see significant natural loose snow avalanching on steeper slopes.
Recent Avalanche Activity
Yesterday’s storm left lower density snow covering our advisory area. Low visibility prevented gathering field observations. In the past few days, a few pockets of windslab to size D1 were observed primarily above 3000′ in the lee of ridges and gully walls. Similarly, in Moonlight Basin skiers triggered shallow windslab which propagated across the feature. These concerns remain relevant.
Near the port, some stormslab avalanches to size D2 fell out of steep rocky rollovers above 3000′. Some evidence of wet avalanches to size D2 in steep gullies below 3000′ from the Dec.2-14 storm. With temperatures consistently below freezing now, we don’t expect further wet avalanche activity.
|WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:|
|Temperature Forecast (Min/Max *F):||14/28|
|Ridgetop Wind Forecast (direction/mph):||SE/6-20|
|Snowfall (in/water equivalent):||0″ /0.1″|
|WIND & TEMPERATURE
PAST 24 hours
|Ferry Terminal||Thompson Pass|
|Average Wind Speed (mph) / Direction||4 /NE||20 /W shift to SE|
|Max Wind Gust (mph) / Direction||10/W||39 /SE|
|Temperature Min / Max (*F)||24 /28||15/24|
Cloudy today with light winds. Trace amounts of snow possible.
Additional Info & Media
|SNOW HISTORY:||Valdez 12/20 AM||Thompson Pass 12/20 AM|
|24 Hour Snow / Water Equiv.||13”/ 0.8″||10″ /0.1″|
|Storm Snow /Water Equiv. [12/19]||10.0″ /1.0″snow+rain||10″ /1.0″|
|Current Snow Depth||27″||69″|
|December Snow / Water Equiv.||51″ /13.97″||142″ / 18.7″|
|Total Winter Snowfall / Water Equiv.||64″ /16.22”||207″ / 24.2″|
|Snowload in Valdez||45 lbs/sq. ft.|
|SNOWFALL at OTHER STATIONS:
LAST 24 HRS (12/19 AM)/STORM TOTAL (12/10-18)/STORM WATER EQUIV.:
|Nicks Valley at 4200 ft (in):||0″ / ?” / ?”|
|Upper Tsaina at 1750 ft (in):||0″ / ” /1.9″|
|Sugarloaf at 550 ft (in):||0″/ ” /3.8″|
|SNOW DEPTH & WATER SURVEY (12/2017)||Depth||Snow Water Equivalent|
|Milepost 2.5 Valdez||″||″|
|Milepost 29 Worthington Flats||″||″|
|Milepost 37 Tsaina River bridge||″||″|
|This survey is done the first week of each month.|
- Northeast Prince William Sound NWS Weather Forecast
- Middleton Island Radar for Valdez area
- GOES Alaska water vapor satellite loop
- NOAA NWS Recreational spot forecast for Thompson Pass
- Thompson Pass MP 25.7 RWIS weather station 2740′ (Mesowest)
- Valdez Marine Ferry Terminal weather station sea level
- Nicks Happy Valley above MP 30 weather station 4200′ (scroll to Nicks Valley)
- Upper Tsaina River Snotel near MP 32 1750′
- Sugarloaf Snotel 551′
- Above Valdez Glacier Cryosphere program weather station 6600′ <map here>
- Valdez Blueberry Weather Plot observations (scroll to bottom: Valdez City)
- More Mountain Weather resources for Alaska
- GFS 16 Day Model for Valdez
- Model Average Meteogram for Valdez
SNOW CLIMATE ZONES:
- Maritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
- Inter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
- Continental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).
Photo of Thompson Pass
Interactive Map of Valdez Forecast Areas w/ Many Resource Layers (Trevor Grams)
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.