Northern San Juan
SnowpackAdam Babcock · Mar 17, 2013 · Northern San Juan
Weather
High winds at ridge top (est. 55mph), WNW. Relatively warm temps, 30degF. 3-5 cm new snow last 24hrs, just enough to blow around. Wind transported snow = fair amount saltation up to 2m height off ground. Plumes visible on far away peaks, 10's of m into the air. Most loading = cornice development and 10-15m below cornice line in the eddy...I suspect much of the blowing snowing lost to sublimation.
Snowpack
Cornice development moderate but reactive. At 1426 I witnessed a natural cornice failure, D1, at treeline on the Battleship ridge, 40-50m wide, ran 15-20m, did not trigger anything on slope below. I subsequently stomped cornice on same ridge in safe locations w/similar results: cornice failures would propagate 5m in front of my skis at most, and would not trigger anything on light-to-moderately wind-loaded slopes below. Soft windslab development of 1F/1F+ ("wind chalk") near ridge lines, variable thicknesses. Could be significant load in pockets, but not widespread. Evidence of surface hoar from night before, blown over near & above treeline. Also interesting, surface warming from days prior created thin (1cm) "zipper" crust on N aspects: N trees off Battleship ridge and N chutes opposite Sam's Trees (Mill Creek? Chattanooga?).