Observation: Skyline 12/24/2009

Observer Name:

Grant Helgeson

Region:

Skyline

Weather

Sky:

Few

Wind Direction:

Northwest

Wind Speed:

Moderate

Weather Comments:

Brrrrr. Chilly day on the skyline. 4 F in the morning, warmed to around 10 F. Northwesterly wind is cross loading slopes in the alpine where ridge top transport was moderate. Cold temps continue to facet our shallow pack.

Snow Characteristics

New Snow Depth:

Snow Surface Conditions:

Powder

Wind Crust

Snow Characteristic Comments:

Unlike our cousins to the North, the Skyline received a 4 inches on Wednesday night. East facing aspects are clearly loading up as the wind piles the new snow on lee aspects.

Red Flags

Wind Loading

Cracking

Red Flag Comments:

Got a bit of cracking & collapsing still in area's of shallow snowpack. The recent storms are bridging the weak layers in areas with a thicker pack. Still potential for human triggered avalanches in areas of shallow snowpack, i.e. near rock outcroppings.

Primary Concern

Primary Concern:

Persistent Slabs

Probability:

Moderate

Aspect:

North

Northeast

East

Elevation:

High

Trend:

Same

Primary Concern Comments:

The facets are alive and well on the ground. I saw quite a bit of the forecast area, but did not see any natural activity. Facets are getting harder to trigger, but the potential exist for them to fail. If a rider triggers the facets, the slope will avalanche to the ground. 30 - 50 inch crowns would not surprise me.

Moderate X. Persistent slabs are getting harder to trigger, but, when triggered, they have potential to be large & destructive.

Secondary Concern

Secondary Concern:

Wind Slabs

Probability:

Moderate

Aspect:

East

Southeast

Elevation:

High

Mid

Trend:

Less Dangerous

Secondary Concern Comments:

Winds appear to be dying down during the day (Chirstmas) but, shallow wind slabs are sensitive on lee aspects. Slabs should be manageable for the most part in moderate terrain. This may not be the case on steep high elevation slopes.

snow_profile_location:

Comments - Photos - Videos (group 1)

Allison stomps on a small east facing test slope and triggers a shallow yet sensitive wind slab. Use small test slopes to your adva

Video 1:

Observed Danger Rating:

Moderate

Forecast Danger Rating:

Moderate