Springtime conditions: avalanche danger decreases with overnight cooling and increases with daytime warming.
Plan your day to minimize your exposure to steep slopes later in the afternoon.
Friday April 14: VAC Full Moon Spring Fling FUNraiser with Acoustic Avalanche at the Tsaina Lodge
Above 2,500ft Moderate
1,800 to 2,500ft Moderate
Below 1,800ft Moderate
Degrees of Avalanche Danger ?
|SUNDAY||MONDAY||TUESDAY & WEDNESDAY|
Elevation: Below 5000′
Aspect: South, East in AM, West in PM
Terrain: Steep terrain near rocks and vegetation.
Sensitivity: Touchy when warmed.
Likelihood (Human Triggered): Likely
Danger Trend: Increasing quickly each day with warming temperatures, falling at night
Forecaster Confidence: Good
Elevation: Above 2500′
Terrain: Slopes > 35*
Sensitivity: Stubborn on northerlies, Touchy when warmed by sun
Likelihood (Human Triggered): Possible
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>
Inter-Mountain (Transitional) Specific: Monitor where surface hoar and near surface facets are being buried by fresh flurries.
The storm that ended April 6 laid down 2-4 inches of water equivalent in our upper elevations; 3-4 feet of snow up high on the coastal side with rain below ~3600′. Much less precipitation fell interior of Thompson Pass.
The storm snow is reportedly settling and bonding well to old layers. The exception is a few upper elevation areas where buried near surface facets are still reactive. South wind during that storm formed new cornices and some pockets of windslab near and below ridgelines. The tail end of the precipiation, April 4-6, pushed temperatures above freezing to 4500′ on the north side of the pass and up to 5500′ in the maritime.
Daytime green house effect (short wave radiation bouncing between the snow surface and cloud cover) and periods of direct sunshine caused wet loose activity to entrain and step down, releasing slab avalanches to size D3 April 6-8. In really shallow areas, wet loose has scoured directly to the ground.
Persistent slab problems are still a concern in colder, thinner and more continental areas. The structure is very poor and the potential for a storm slab or hard slab to step down to weak basal facets is scary. Continue to monitor this structure as temperatures rise and weaken the firmer, overlaying structure.
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
Inter-Mountain (Transitional) Specific:
- April 6-8: wet loose avalanches on southerlies have stepped down to large D3 slabs (peeling entirety of the last storm snow off old firm surfaces) that have run far into the flats. Mostly in lower elevations under 4500, but some higher.
- April 3 small D1 avalanches triggered on southerly aspects at high elevations.
- April 3: Hard wind slab collapse reported near the top of couloirs/ridgeline
- April 2: human triggered small (D1) wind slab avalanche reported on a southerly aspect, released from thin coverage on rocks above
- March 31: D2 human triggered avalanche on N aspect at 3500′
See Maritime Zone for updated weather.
Additional Info & Media
- 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.