Thanks to everyone who participated in the VAC fundraiser Friday night at the Tsaina Lodge!
Above 2,500ft Moderate
1,800 to 2,500ft Moderate
Below 1,800ft Moderate
Degrees of Avalanche Danger ?
|Monday||Tuesday||Wednesday & Friday|
Elevation: Below 4500′
Aspect: SE – S – SW
Terrain: Southerly facing terrain on slopes above 30 degree slope angle
Sensitivity: Non-reactive when frozen – Responsive when warmed by above freezing temps and direct solar input
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing with solar input and above freezing temperatures
Forecaster Confidence: Good
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: The annual spring shed cycle is well underway. Temperatures around Thompson Pass have been above freezing during the day, with the surface of the snowpack freezing solid over night. This cycle can produce corn snow but is also the precursor to surface instability and an isothermic snowpack.
Snow surface conditions above ~3000′ are widely variable. Conditions on northerly facing slopes range from wind scoured pencil hard sastrugi, melt/freeze, to decomposing unconsolidated particles. Southerly faces are experiencing a range from heavy wet snow, to melt freeze crusts, to corn, to isothermal.
Snow depths generally range from 30-300cm, including on glaciated terrain.
Check out our public observations.
Recent Avalanche Activity
From the port of Valdez up to 4500′ throughout the advisory area: numerous southerly facing slopes above 30* slope angle have begun the spring shed with natural wet avalanches. This wet avalanche activity has been triggered by daytime temperatures above freezing and direct solar input. Many have been initiating in rocky steeps, taking surface snow, but some have stepped down to deeper old layers, pulling out small slabs with them.
Friday & Saturday 4/13 & 14 PM: wet snow avalanches at Three Pigs at Milepost 39 ran to the middle of the highway.
While the snow is frozen, the avalanche danger is low with natural and human triggered avalanches unlikely. As the day heats up and solar input increases, the snow warms and avalanche danger rises with human and natural triggered avalanches likely.
|WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:|
|Temperature Forecast (Min/Max *F):||15 / 35|
|Ridgetop Wind Forecast (direction/mph):||NE/20|
|WIND & TEMPERATURE
PAST 24 hours
|Ferry Terminal||Thompson Pass|
|Average Wind Speed (mph) / Direction||4 / NE||15 / NE|
|Max Wind Gust (mph) / Direction||16 / NE||27 / NE|
|Temperature Min / Max (*F)||33 / 49||12 / 34|
Weather Forecast: Sunny with light winds Monday and Tuesday. Chance of snow Wednesday with maybe an inch to a few inches accumulating by the weekend. Another chance of snowfall over the weekend. Dirunal spring temperatures with warm days and overnight freezes. Light winds throughout.
Additional Info & Media
|SNOW HISTORY:||Valdez 4/16 AM||Thompson Pass 4/16 AM|
|24 Hour Snow / Water Equiv.||0”/ 0.0″||0″ / 0.0″|
|Storm Snow /Water Equiv. (3/15-19)||19” / 0.41″||40″ / 1.5″|
|Current Snow Depth||21″||63″|
|April Snow / Water Equiv.||0″ / 0″||1″ / 0.1″|
|Total Winter Snowfall / Water Equiv.||132.59″ / 27.2”||373″ / 36.7″|
|Snowload in Valdez||40 lbs/sq. ft.|
|SNOW DEPTH & WATER SURVEY (3/4/2018)||Depth||Snow Water Equivalent|
|Milepost 2.5 Valdez||32.2″||9″|
|Milepost 29 Worthington Flats||62.4″||21.2″|
|Milepost 37 Tsaina River bridge||58.4″||14.2″|
|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.