April Fools Gaper Day – Tuesday 4/1-4/4
Issued: Sat, Apr 01, 2017 at 8AM
Expires: Tue, Apr 04, 2017
Hope you have your foolish Gaper Day outfit ready to wear in the mountains today….get out and enjoy it!!! It is snowing up high!
As warm rain and weight continue to be added to the snowpack, monitor how the snow structure is adjusting and how the water is draining down into the snowpack….possibly melting and weakening deeper buried layers.
Wet loose will pull out of steep terrain and wet slabs could release, especially near buried crusts.
Friday April 14: VAC Full Moon FUNraiser with Acoustic Avalanche @ Tsaina Lodge
Above 2,500ft Considerable
1,800 to 2,500ft Considerable
Below 1,800ft Considerable
Problem Details
| SATURDAY | SUNDAY | MONDAY & TUESDAY |
|---|---|---|
 |
|
 |
DANGER SCALE |
STORM SLAB:
Elevation: All
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Widespread
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing
Forecaster Confidence: Good
WET LOOSE:
Elevation: <3000′
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Widespread
Likelihood (Human Triggered): Possible
Size: Small
Danger Trend: Increasing
Forecaster Confidence: Fair
WIND SLAB:
Elevation: Above 2500′
Aspect: various aspects
Terrain: shallow snowpack near ridges, rollovers, gullies with facets underneath
Sensitivity: Responsive
Distribution: Fresh windslab where sits over facets or hasn’t yet bonded.
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increading
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>
SNOWPACK DISCUSSION:
Inter-Mountain (Transitional) Specific:
Snow up high and rain down low continues to accumulate on top of an already upside down snowpack. Expect wet snow activity to continue to show itself today as warm temperatures and rain will persist into tomorrow evening.
On Thompson Pass (and likely elsewhere), 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 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 will likely 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 on Wednesday.
The further you get from the pass the new snow levels seem to dramatically decrease. This has been a trend all season, with most of our storms hammering the maritime zone, while leaving the intermountain/continental zones high and dry.
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:
Poor visibility have limited observations: please share if you have seen anything!!!
- March 28 an Avalanche was reported on the Road Run.
- Human triggered avalanches sizes D2-2.5 likely on steep wind affected rollovers, ridgelines, and gully walls.
- March 25 reports of upper elevation (>4500′ elevation) human triggered windslabs to a foot thick releasing off steep slopes. With a D1.5 remotely triggered slide on a southerly aspect between 4,500′-5,500′.
Loose snow triggered soft slab: ~30cm crown. Gully One (Vertigo)
- March 24: Small D1 R1 skier triggered wind slab on the west facing wall of Snatch (Gully 2). Recently loaded by NE outflow winds
Recent Weather
See Maritime Zone for updated weather.
Additional Info & Media
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
- Windty
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.
