Friday April 14 bon fire: VAC Full Moon FUNraiser with Acoustic Avalanche at the Tsaina Lodge
Above 2,500ft Moderate
1,800 to 2,500ft Low
Below 1,800ft Low
Degrees of Avalanche Danger ?
|TUESDAY||WEDNESDAY||THURSDAY & FRIDAY|
Elevation: Above 2500′
Aspect: aspects lee of south-southwest storm wind
Terrain: shallow snowpack near ridges, rollovers, gullies with facets underneath
Distribution: Fresh windslab where sits over facets or hasn’t yet bonded.
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing
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:
With the last two days of good lighting Thompson Pass has had many great slope tests from snowmachiners, boarders & skiers. Small (D1) wind slabs were triggered in the inter-mountain zone. This warrants concern for unsupported wind loaded slopes in upper elevation ridgetops, gullies and convexities in the maritime side. The danger trend is increasing with the new snow from last night.
On Thompson Pass a couple new melt-freeze crusts have formed up to ~2600′. A thinner (1″, 4F) crust near the surface sandwiched several inches of soft snow between a thicker (~3″; 1F+) melt freeze crust almost a foot down. Hand shear testing Friday demonstrated poor crust bonding with very easy results when isolating columns. Propagation was supported at ~2400′ on Thompson Pass on Thursday, when a large collapse occurred of the new storm snow (thick crust and everything above) resting on buried facets below. In areas where the facets did not reside, bonding of new snow was good.
Evaluation of the snowpack down near Cracked Ice Friday showed much better bonding and no propagation. See recent observation.
Higher elevations exposed to wind have fresh wind slab formation that has been bonding well to underlying snow thus far (Q3 w/ steps), unless it is sitting on a persistently weak grain (old facets). A small collapse of newly blown in shallow slab on rocks occurred at ~3000′ on Thompson Pass on a southerly aspect.
Human triggered avalanches were reported on the road run earlier this week and slab and wet loose snow was moving on very steep slopes around the port during the storm.
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
Maritime (Coastal) Specific:
- March 31: Many small (D1) loose wet avalanches around the port and in Keystone Canyon.
- March 29: 0-1000′ elev. below Comstock: up to 18″ of heavy storm snow was shifting and sliding under foot in steeps with friction: propagation limited.
|WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:|
|Temperature Forecast (Min/Max *F):||30 / 36|
|Ridgetop Wind Forecast (direction/mph):||NE / 2-15|
|Snowfall (in/water equivalent):||1″ / 0.25″|
|WIND & TEMPERATURE
PAST 24 hours
|Ferry Terminal||Thompson Pass|
|Average Wind Speed (mph) / Direction||5 / NE||7 / NE|
|Max Wind Gust (mph) / Direction||15 / ENE||17 / SE|
|Temperature Min / Max (*F)||31 / 42||18 / 30|
Weather Forecast: More snow possible through the week. Clouds will drift through with 1/2 inch water equivalent through Friday. The freezing level dropping to surface, with daytime max near 2500′. Moderate south to east wind.
Additional Info & Media
|SNOW HISTORY:||Valdez 4/4 AM||Thompson Pass 4/4 AM|
|24 Hour Snow / Water Equiv.||0”/0.04″||2″ /0.2″|
|Storm Snow /Water Equiv. (3/27-4/3)||16.9″ /4.1″||23″ /2.3″|
|Current Snow Depth||43″||45″|
|April Snow / Water Equiv.||~″ /0.47″||8″ / 0.8″|
|Total Winter Snowfall / Water Equiv.||240.8″ /23.7”||327″ / 31.4″|
|Snowload in Valdez||65.0 lbs/sq. ft.|
|SNOWFALL at OTHER STATIONS:
LAST 24 HRS (4/4 AM)/STORM TOTAL (3/27-4/2)/STORM WATER EQUIV.:
|Nicks Valley at 4200 ft (in):||1″ / ~16″ / ?”|
|Upper Tsaina at 1750 ft (in):||1″ / ?” / 1.2+”|
|Sugarloaf at 550 ft (in):||.5″/ 20+rain” / 2.8″|
|SNOW DEPTH & WATER SURVEY (4/2/2017)||Depth||Snow Water Equivalent|
|Milepost 2.5 Valdez||41.9″||11.9″|
|Milepost 29 Worthington Flats||62.2″||19.6″|
|Milepost 37 Tsaina River bridge||46.3″||12.5″|
|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.