A dusting of new snow could mask hazards and changes in snow conditions….no longer able to read the old snow surface texture for predictability. That concern combined with low light should result in conservative travel styles.
Steep, unsupported windslab in upper elevations could still pose hazards.
Above 2,500ft Moderate
1,800 to 2,500ft Low
Below 1,800ft Low
Degrees of Avalanche Danger ?
|THURSDAY||FRIDAY||SATURDAY & SUNDAY|
Elevation: Above 1800 feet elevation
Aspect: South and west
Terrain: Steeper than 35 degrees; unsupported
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Decreasing
Forecaster Confidence: Poor
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>
Inter-Mountain (Transitional) Specific:
Near ridgetops and wind channeled terrain, the north wind has transported the unconsolidated surface snow and formed windslab on leeward slopes. Much of the high ground is wind affected and scoured. Many pockets of hard windslab naturally popped off rollovers and steep gully ways last weekend with little to no new activity since. Poke around to see how the windslab is bonded to layers below. Soft snow is still found in wind protected valleys. Some surface hoar observed.
It is a variety pack out there….snow”pack” that is….of the not so desirable type….where you yearn for only one of the options in the mix (soft snow), but the less desirable options dominate the package. If one wanders out right now you will find it all: rocks, tundra, exposed lake ice (Odyssey), sastrugi, wind board, decomposing snow, near surface facets, surface hoar, and even melt-freeze crusts. It all depends on where you go, but most of the upper elevations have been wind hammered and require reserved travel speeds. Things are pretty thin overall, a lot of rock showing and very old, early season layers continue to resurface.
Prior to the 3 inches last night, the last snowfall ended more than a week ago, Jan.31. Since then, the storm snow has settled and bonded to snow beneath fairly well. The north wind has moved and textured much of the snow. Feb.1-5 was the return of sun affect: solar radiation and warm daytime temperatures triggered roller balls and loose avalanches on southerly aspects, sometimes trenching to the ground near town. It was a dramatic shift from early season to more spring-like snow conditions that brought above freezing temperatures all the way up to Thompson Pass.
Things cooled off significantly and now slightly warmed with this front. Very light, dry flakes have dusted the mountains.
While out in the colder side of the inter-mountain zone Wed, Feb 8th, I was able to get my first propagation in an ECT in awhile….2 results actually. This is at nearly 5000′ on a SE aspect below Max Low…~MP 33. ECTP13 RP in the decomposing fragments below wind board (down 20cm) and ECTP30 SC in the weak basal 2-4mm depth hoar at the ground. This demonstrates the continued weak structure at the bottom of our pack and stirs up the question: What forces and circumstance could fail this weak and stubborn layer, taking the whole snowpack with it? Keep an eye on it, especially as temperatures warm this spring.
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:
- No new observations reported.
|WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:|
|Temperature Forecast (Min/Max *F):||5 / 20|
|Ridgetop Wind Forecast (direction/mph):||NE / 10-35|
|WIND & TEMPERATURE
PAST 24 hours
|Ferry Terminal||Thompson Pass|
|Average Wind Speed (mph) / Direction||3 / NE||12 / Var|
|Max Wind Gust (mph) / Direction||8 / NNE||28 / NE|
|Temperature Min / Max (*F)||17 / 25||-1/ 18|
Weather Forecast: The weak front that arrived yesterday, ushered in moderate southerly winds and warming temperatures with 3 inches of light snow on Thompson Pass and a dusting in town. Since then, winds have reversed…back to to a NE outflow. As the low pressure lingers in the gulf over the next day or two, trickles of light snow could double our current totals and continue until early Saturday when skies will likely open up. Starting Sunday morning, clouds will return with random snow, but precipitation should pick up dramatically early Monday and into next week.
Additional Info & Media
|SNOW HISTORY:||Valdez 2/9 AM||Thompson Pass 2/9 AM|
|24 Hour Snow / Water Equiv.||0.4”/Trace”||3″ /0.2″|
|Storm Snow /Water Equiv. (2/8-9)||0.4” /Trace″||3″ /0.2″|
|Current Snow Depth||37.4″||39″|
|February Snow / Water Equiv.||3.1″ /0.2″||6″ / 0.4″|
|Total Winter Snowfall / Water Equiv.||181″ / 16.1”||245″ / 23.1″|
|Snowload in Valdez||50 lbs/sq. ft.|
|SNOWFALL for LAST 24 HRS at OTHER STATIONS:|
|Nicks Valley at 4200 ft (in):||Trace?”|
|Upper Tsaina at 1750 ft (in):||Trace?”|
|Sugarloaf at 550 ft (in):||Trace?”|
|SNOW DEPTH & WATER SURVEY (2/1/2017)||Depth||Snow Water Equivalent|
|Milepost 2.5 Valdez||41.5″||9.8″|
|Milepost 29 Worthington Flats||61.5″||16″|
|Milepost 37 Tsaina River bridge||42.1″||9.3″|
|This survey is done the first week of each month.|
- 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.