Front Range
AvalanchePaul Rogers · Dec 27, 2013 · Front Range
Weather
Calm winds 5 mph even at ridge top from NW and North. No blowing snow. Temps in high twenties except for inversions at valley bottoms where it was significantly cooler - even mid-day/afternoon. Felt as if it was 10-15 degrees cooler at valley bottoms but did not take temp reading.
Snowpack
Surface: Widespread Surface Hoar formation all aspects & elevations toured-even at ridge top. Below TL on S-E aspects sun and warm temps were impeding/destroying yet elsewhere it was unaffected. Below TL: snowpack was weak and faceted. At & Above TL: Obvious and pronounced wind slab formation from recent storm snow, N-SE aspects - observed up to 2/2.5 feet. Resting on crust/facet, facets or depth hoar depending on aspect. We observed primarily soft slab in our location/elevations. Easy test results, yet except for few isolated examples (like TeaCup bowl), cohesive nature of soft slab was such that it did not propagate far/wide - in the area we toured. Expect this to change as slab stiffens. Observed 1F, 20-30cm thick persistent slab, N'rly aspects in specific wind-loaded areas, resting on depth hoar or crust/facet layer. It was stubborn to get to move in tests but when it did, it was clean, smooth planar shears. Skiing quality: Great at/above TL on N'rly aspects. Not fun below TL in trapdoor faceted snow.
Avalanche
Observed the human triggered slide at Teacup bowl, which has been previously reported. There is another steep feature, just to the north of Teacup bowl, East aspect, same elevation, which often slides: Skiers had entered feature, it collapsed and propagated but did not slide - not cohesive enough to form soft slab -- yet!