Sunday-Wednesday 1/28-1/31
Issued: Sun, Jan 28, 2018 at 8AM
Expires: Wed, Jan 31, 2018
Avoid crossloaded gully walls and actively loading lee features. If the snow begins to get stiff, sound hollow, or you see shooting cracks, choose another slope without wind affect. Dig and test for the persistent weak layer between 2 and 4′ below the surface. Windchill is significant.
Above 2,500ft Moderate
1,800 to 2,500ft Moderate
Below 1,800ft Low
Problem Details
| Sunday | Monday | Tuesday & Wednesday |
|---|---|---|
 |
|
|
DANGER SCALE |
WIND SLAB:
Elevation: Above 2000′
Aspect: Lee of ridges, gullies, ridgetops
Terrain: All terrain exposed to wind
Sensitivity: Responsive
Distribution: Specific
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Steady
Forecaster Confidence: Good
PERSISTENT SLAB:
Elevation: Above 2500′
Aspect: All
Terrain: 35+ degrees steepness
Sensitivity: Stubborn
Distribution: Specific
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Steady
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>
SNOWPACK DISCUSSION:
Strong northerly outflow wind continues to redistribute surface snow and build fresh wind slab. Our last notable storm was Jan.13-16 with totals ranging from 18’’ (46cm) near Kenny Lake/Chitina to 41’’ (104cm) at Thompson Pass. Expect scoured ridgelines, while lee slopes could have very deep pockets of fresh windslab.
Previous to the Jan.13-16 storm there were concerns of a persistent weak layer about 1-2’ under the snow surface. This persistent weak layer (surface hoar and/or near-surface facets) is now buried 2-4’ down. We suspect this layer may persist in upper elevations primarily where wind had less effect. We encourage you to dig for and test this layer, especially above 3000′. 1/26 on a NW aspect across from Rice Mountain at 3200′, we found this layer 28″ (70cm) below the snow surface and it was stubborn to trigger.
Below 2000′ (the rainline from the Jan.13-16 storm) the snow is frozen in place with a beefy crust.
Recent Avalanche Activity
January 19, a snowmachiner triggered an avalanche size D2 between Heiden Glacier (near “The Books”) and Deserted Glacier. The weak layer may have been near-surface facets.
- NW aspect
- ~35< slope
- ~5000′ in elevation
- 1-3′ (30-91cm) crown
- No injuries reported
See photo and map below. Photo credit: Clyde Hewitt.
Several small windslab avalanches size D1 were observed Thursday Jan.18 at 3200′, visible from the Loveland parking lot to the lee of gullies. These seem to have been naturally triggered and were likely a day or two old. All of them were facing southeast, which indicate they were created by a northerly outflow wind.
No other reports of avalanches, whumphing or cracking have been reported since Jan. 19th.
Recent Weather
| WEATHER FORECAST for NEXT 24 HRS at 3,000 ft: | ||||
| Temperature Forecast (Min/Max *F): | -14/ 15 | |||
| Ridgetop Wind Forecast (direction/mph): | NE / 30-50 | |||
| Snowfall (in): | 0 | |||
| WIND & TEMPERATURE PAST 24 hours |
Ferry Terminal | Thompson Pass |
| Average Wind Speed (mph) / Direction | 10/ NE | 36 / NE |
| Max Wind Gust (mph) / Direction | 21 / NE | 50/ NE |
| Temperature Min / Max (*F) | 13 / 19 | -10.5 / -4 |
Weather Forecast: Clear and cold. Strong northerly outflow wind. Temperature inversion possible today.
Additional Info & Media
| SNOW HISTORY: | Valdez 1/28 AM | Thompson Pass 1/28 AM |
| 24 Hour Snow / Water Equiv. | 0”/ 0″ | 0″ / 0″ |
| Storm Snow /Water Equiv. (1/13-16) | 2” / 2.82″ rain | 41″ / ~3″ |
| Current Snow Depth | 23.5″ | 80″ |
| January Snow / Water Equiv. | 12.78″ / 6.02 ″ | 73″ / ~6.5″ |
| Total Winter Snowfall / Water Equiv. | 77.64″ / 22.05” | 281″ / ~30″ |
| Snowload in Valdez | 37 lbs/sq. ft. |
| SNOWFALL at OTHER STATIONS: LAST 24 HRS / STORM TOTAL (Jan.13-16) / STORM WATER EQUIV.: |
||||
| Nicks Valley at 4200 ft (in): | 0″ / 22″ / ?” | |||
| Upper Tsaina at 1750 ft (in): | 0″ / 19″ / 2″ | |||
| Sugarloaf at 550 ft (in): | 0″ /rain” / ?” | |||
| SNOW DEPTH & WATER SURVEY (2/1/2017) | Depth | Snow Water Equivalent |
| Milepost 2.5 Valdez | ″ | ″ |
| Milepost 18 | ″ | ″ |
| Milepost 29 Worthington Flats | ″ | ″ |
| Milepost 37 Tsaina River bridge | ″ | ″ |
| This survey is done the first week of each month. | ||
Weather Quicklinks:
- 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
- Windy
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)
Run Map of Thompson Pass Area (Sean Wisner) (2MB download)
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.
