Location: Crested Butte Area
Date of Observation: 03/31/2016
Name: Zach Guy
Subject: Sluffs and variable persistent slab results
Aspect: North, North East
Avalanches: Skier triggered one D1 loose dry avalanche, which ran about 500 vertical feet, big enough to bury someone if it was in a gulley.
Weather: Few clouds this morning quickly built to overcast, then decreased to scattered. S-1 to S1 midday, with maybe an inch of total accumulation. Light valley winds from the west, calm winds elsewhere where we traveled.
Snowpack: 4″ of low density new snow over older settled powder; sluffing easily but no storm slab concerns. Dug 4 pits on northerly slopes and found a mix of propagating and non propagating results on the March 6 facet layer, 18″ to 3 ft deep. Structure was most concerning mid slope near treeline, 500-1000 ft below the windloaded ridgeline, where the slab thinned but was still stiff enough for propagation.
1.) BTL N aspect: 45 cm slab over 1mm rounding facets; no distinct hardness change and no results ECTs
2 & 3.) NTL N and NTL NE (tree shaded) at windloaded ridgeline. 90-100 cm slab (4F+ or 1F-), over 4F-, 1-1.5mm rounding facets. Hard ECTN results and SC Compression test results.
4.) NTL NE, midslope. 4F+ 60 cm slab over F+ rounding facets on an almost in-perceivable faceted crust. ECTP14, SC results. See photo.
Propagating extended column test results on a NE aspect NTL