None
Observation: Summit
Location: Butch
Toured up to 2650′ on Butch’s Northwest shoulder. A stout to lightly breakable melt freeze crust is present on N and W slopes up to ~2400′. Softer near surface facets covered most surfaces at all elevations. Warming of the sun noted on lower elevation slopes in afternoon.
Observer Comments
Weather
Partly cloudy transitioning to overcast with flurries at 1300. Flurries continued to the end of our tour around 1530. Calm winds. Upper 30s F at valley bottoms and lower 20s F at ridgetops.
Snow surface
A melt freeze crust was present up to ~2400' on N to W aspects. This melt freeze crust was 1.5" thick at valley bottoms and stout on skis, decreasing in thickness and becoming slightly breakable at around 1800'. This crust was covered with a dusting of new snow on top of 1-3" of near surface facets that warmed up in the afternoon. Above 2000' the surface became more wind affected in open meadows and on ridgelines with a mix of either near surface facets, soft sastrugi, or wind crusts. At our highpoint at 2700' stout wind slab was present near the location of the remotely triggered avalanche on Butch March 12th.
Snowpack
Probing in mid elevations between 2000-2500' weak facets could be felt beneath the buried January melt freeze crust. We dug two pits near the location on the remote triggered avalanche on Butch March 12th.
Pit 1: 2650', N, 19 degree slope, HS/TD=150 cm. CT16 & 21 SC on 3-6 mm cupped fist hard basal facets. CTN. ECTX. DTN.
Pit 2: 2650', NNW, 31 degree slope, HS/TD=165cm. Found 2mm facets on m/f crust 75cm (30") below the surface. The bottom 1/2 of pit was a mix of deteriorating m/f crusts and facets. Only had failure in one compression test 120cm below the surface on 2mm facets between crust. This interface was uneven and facets were moist. Other tests: CTNx2
Poor structure in Pit 1 on Butch at 2650' with weak basal facets under a hard slab.
Surface conditions at ~2200. Soft wind affected snow and near surface facets present in open meadows.
Near surface facets and supportable wind slab present along the ridgeline at 2650'.
Poor structure in Pit 2 at 2650' near the location of the March 12 remote triggered avalanche
Southerly wind stripped locations have become darker and more pronounced since last week, evidence of warming of the sun. Photo of Manitoba.
Colorado
Summit
Fresno