Remember: Low danger does not mean no danger.
As winds have picked up, expect new windslabs drifted onto northerly slopes by southerly onshore winds. These are very easily forming on top of widespread surface hoar and near surface facets from our long clear, cold spell.
ALWAYS use safe travel techniques to your advantage, even when feeling confident about the conditions. Only expose one person at a time to terrain features that could avalanche.
Above 2,500ft Low
1,800 to 2,500ft Low
Below 1,800ft Low
Degrees of Avalanche Danger ?
|WEDNESDAY||THURSDAY||FRIDAY & SATURDAY|
Elevation: Above 3000′
Aspect: Various aspects due to shifting winds
Terrain: Near ridgelines, rollovers, and gully walls
Likelihood (Human Triggered): Possible
Size: Small – 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
AVALANCHE PROBLEM TOOLBOX <here>
Inter-Mountain (Transitional) Specific:
30″ of heavy snow, mixed with rain below ~3000′, fell around the Thompson Pass region last week. A widespread avalanche cycle occurred during this storm, flushing out any persistent weak layers deeper in the snow pack. Make a mental note of where these large avalanches occurred, for areas that didn’t slide could still harbor problems.
Over the long calm, clear and cold spell, widespread surface hoar and near surface facets formed throughout our region. As new snow falls and winds pick up, investigate how these weak crystals are reacting once they get buried. Evaluate and test readily, for these crystals can persist and lead to problems for extended periods of time….leading to unpredictable and large avalanches.
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:
Observed Feb. 18:
- Numerous large(D3+) Wet Slab avalanches ran during the storm last week in the Tsania Valley that hit the valley floor
- Natural Sluffs (Loose Snow) Observed on North Aspects in the Tsania Valley(before the glacier), while no natural activity was observed in the Tonsina Glacier area
Observed Feb 16:
- Many mid storm avalanches released up to D2.5 off of steep faces: Several on north face of Odyssey, School Bus, Vertigo, Snatch, 40.5 Mile Ridge/Wilburs
- Extensive shallow slab releases on mid+ elevation southerly aspects below Bald Boy to Hippy Ridge (MP 29-37): seemed to be pulling out on persistent weaknesses: likely surface hoar or near surface facets formed last week.
- Large deeper avalanche releases on basal weaknesses at the ground below Max Low and Wilbur’s on 40.5 Mile Ridge
Reported Feb.13-15 during the storm:
- Large avalanches at Milepost 38, 42, and 50
See Maritime Zone for updated weather.
Additional Info & Media
- 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:
- 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.