Yet another round of gusty outflow wind has further scoured into our snowpack….mostly in in very high, exposed terrain.
Look out for new layers of wind slab recently top and cross loaded into lee terrain. Evaluate older slabs for bonding to underlying snow (crusts to facets to wind board) which could still be sensitive.
Above 2,500ft Moderate
1,800 to 2,500ft Low
Below 1,800ft Low
Degrees of Avalanche Danger ?
|THURSDAY||FRIDAY||SATURDAY & SUNDAY|
Elevation: Above 2000′
Aspect: Lee to northerly winds
Terrain: Near ridges, gullies, rollovers
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>
Maritime (Coastal) Specific:
It has been 2 weeks since a snowflake has fallen from the sky and 11 days since the strong north winds started wreaking havoc on our snowpack. These extreme winds, that peaked near 90 mph, have scoured deep into older snow and drifted snow into low lying gullies, trees, crevasses and rollovers. Many natural wind slab avalanches released throughout our region while few human triggered were reported, likely due to the inhospitable conditions. Wind affected areas have knife hard windslab, sastrugi, rain/melt-freeze crusts and wind scoured bare ground. The main concern is windslab over ice crust, buried surface hoar and near surface facets. Steep southerlies in the lower elevations are melting out to bare ground.
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Recent Avalanche Activity
Maritime (Coastal) Specific:
- Mar. 2: More natural wind slabs to size 2 pulling off steep ridgelines and rollovers in terrain exposed to strong northerly outflow wind.
- Feb. 28: Commonly seen during strong outflow winds, natural avalanches to D2 have pulled off the rollovers on the south side of Odyssey just above the hairpin.
|WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:|
|Temperature Forecast (Min/Max *F):||-1 / 8|
|Ridgetop Wind Forecast (direction/mph):||NE / 20-50|
|Snowfall (in/water equivalent):||0.0″ / 0.0″|
|WIND & TEMPERATURE
PAST 24 hours
|Ferry Terminal||Thompson Pass|
|Average Wind Speed (mph) / Direction||12 / NE||42 / NE|
|Max Wind Gust (mph) / Direction||34 / NE||65 / NE|
|Temperature Min / Max (*F)||19 / 24||2 / 8|
Weather Forecast: More of the same for the near future: clear with cold outflow winds out of the north. A few high clouds could sneak in tonight and early Friday briefly. Winds will back down slightly this afternoon as the pressure gradient weakens in our region. If this huge high pressure block continues to push west, the better the chances that moisture could move in next week, possibly Tuesday night.
Additional Info & Media
|SNOW HISTORY:||Valdez 3/9 AM||Thompson Pass 3/9 AM|
|24 Hour Snow / Water Equiv.||0”/0″||0″ /0″|
|Storm Snow /Water Equiv. (2/23)||0″ /0″||2″ /0.1″|
|Current Snow Depth||37″||39″|
|March Snow / Water Equiv.||0″ /0″||0″ / 0″|
|Total Winter Snowfall / Water Equiv.||222.8″ /20.9”||283″ / 27.7″|
|Snowload in Valdez||~ lbs/sq. ft.|
|SNOWFALL at OTHER STATIONS:
LAST 24 HRS (3/4 AM)/STORM TOTAL (3/4)/STORM WATER EQUIV.:
|Nicks Valley at 4200 ft (in):||0″ / 0″ / 0″|
|Upper Tsaina at 1750 ft (in):||0″ / 0″ / 0″|
|Sugarloaf at 550 ft (in):||0″/ 0″ / 0″|
|SNOW DEPTH & WATER SURVEY (2/28/2017)||Depth||Snow Water Equivalent|
|Milepost 2.5 Valdez||41.8″||12″|
|Milepost 29 Worthington Flats||63.6″||18.6″|
|Milepost 37 Tsaina River bridge||49.3″||12.5″|
|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.