CAIC

Details

Date: 2016/03/19

Observer: blase reardon
Organization: Forecaster, CAIC

Location

BC Zone: Aspen
Area Description: Maroon Bowl - Green Trees & Dark Hollow/ Slice & Dice. 11700-8200'.

Weather

Ridgeline Wind Speed: 10-20 mph
Ridgeline Wind Direction: NW
Wind Loading: Previous
Temperature: 17 F
Sky Cover: Few
Weather Description: Surprisingly cool, esp in wind. Few/ no clouds. Variable, gusty winds.

Snowpack

Snowpack Description: Snow from storm earlier in the week settling out on shaded slopes; refrozen on sunny.

Snowpack Obsvervation #1

Cracking: None
Collapsing: None
Comments: Surface snow on shaded aspects remains cold and dry. Some thin, breakable wind crusts in open, cross-loaded areas. @ 10950, HS 180 cm, slope not likely to have slid in early February. ~ 40 cm settled snow (F->4F) above 2/19 dust layer. Thin FC above/below this layer, but not producing propagation in tests. ECTN 24/ CT 18 RP. Hand shears @ same interface sticky but eventually produced planar shear. Most concerning areas some hollow, trapdoor spots in what look to be old bed surfaces.

Snowpack Obsvervation #2

Comments: Some rollerballs from several days prior. Once the crust on these slopes softens, Loose Wet slides will be possible.

Avalanches

Avalanche Description: Punchy, unsupportable snow in vicinity of 3/18/16 skier-triggered slide. Appeared to be facets above early February bed surfaces.

Media

Images

Figure 1: Looking down the track of a skier-triggered slide from 3/18. The trees make for a classic terrain trap, much like a strainer on a river.

Figure 2: Looking up the steep track of a skier-triggered avalanche on 3/18. Lots of hard things to hit on the way down.

Figure 3: The start zone for a skier-triggered slide on 3/18. Note the variable thickness of the crown - a sign of cross-loading. The slide is a good example of how slopes with variable snow depths - often due to cross-loading - can have numerous potential trigger points.

Figure 4: Another view of the start zone of a skier-triggered slide from 3/18. The slide looks to have broken on soft facets that developed above the bed surface from an avalanche earlier in the season.