CAIC: Colorado Avalanche Information Center BC Zone Observation Report

Saturday, March 19, 2016 at 12:00 AM





  • 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.




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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.
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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.
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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.
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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.