Valdez Snowmachine Club Hill Climb, April 20-21 (22)
Above 2,500ft Low
1,800 to 2,500ft Low
Below 1,800ft Low
Degrees of Avalanche Danger ?
|Saturday||Sunday||Monday & Tuesday|
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
Elevation: Above 2500′
Terrain: Lee of ridges, gullies, ridge tops exposed to wind
Likelihood (Human Triggered): Possible
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
LIST OF AVALANCHE PROBLEMS <here>
SNOWPACK DISCUSSION: Friday 4/20, the advisory area above 2500′ received 1-2″ of high density snow from the SE. In most places, this snow settled with calm winds. The area near Thompson pass experienced winds capable of transporting snow and creating small wind slab to the lee of ridges, gullies and ridge tops.
The advisory area is in the midst of a diurnal spring shed cycle. Temperatures around Thompson Pass have been above freezing during the day, with the surface of the snowpack freezing 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 facing slopes 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
The advisory area continues to experience natural wet avalanches up to 4500′. This wet avalanche activity is primarily on southerly facing slopes and is triggered by above freezing temperatures and direct solar input. Many have been initiated in rocky steep areas, taking surface snow. Some have stepped down to deeper old layers, pulling out small slabs with them.
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):||29 / 31|
|Ridgetop Wind Forecast (direction/mph):||S/5-13|
|WIND & TEMPERATURE
PAST 24 hours
|Ferry Terminal||Thompson Pass|
|Average Wind Speed (mph) / Direction||3 / VAR||18 / SE|
|Max Wind Gust (mph) / Direction||8 / SW||35 / SE|
|Temperature Min / Max (*F)||36 / 39||26 / 28|
Weather Forecast: Saturday cloudy with low visibility, 1″ (2.5cm) snow possible. Sunday cloudy. Temperatures at 3000′ near freezing during the day, below freezing at night. Light to moderate winds.
Additional Info & Media
|SNOW HISTORY:||Valdez 4/21 AM||Thompson Pass 4/21 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||10″||63″|
|April Snow / Water Equiv.||0″ / 0.01″||1″ / 0.1″|
|Total Winter Snowfall / Water Equiv.||132.59″ / 27.21”||373″ / 36.7″|
|Snowload in Valdez||30 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.