Northern San Juan
AvalancheAndrew Temple · Feb 27, 2018 · Northern San Juan
Weather
Moderate winds at ridge lines, clear skies transitioning to few in the afternoon. Temps around -10 to -4 C. all day.
Snowpack
The snowpack in the Ophir zone is roughly 30% shallower than in the RMP zone and noticeably weaker in general. On our approach on westerly slopes the HS varied from about 40-60cm and the snowpack was generally full depth facets or crust/facet combos in all areas we travelled. No slab to speak of BTL on West aspects. Previous winds were strong enough to scour most slopes above treeline on all but NE-E aspects. Most of the start zone of Nevada gulch above TL was scoured. On an easterly aspect near treeline in Swamp, HS 100cm, observed a strengthening snowpack with a 4f-1f midpack slab sitting on a crust facet combo sandwich with no depth hoar observed in the basal layers. With the exception of one ECTP22 down 35 cm. on a rounding non-persistent interface, no test results were noted. There was no collapsing or cracking noted all day.
Avalanche
Observed two large natural avalanches that ran on Monday. One was near Gemini in Waterfall (R2D2.5) and another was just to the north in the next basin (R3D2). These were triggered by wind loading in extreme or steep terrain, the slides caused a slight bit of propagation in the aprons, but not much. No other recent avalanches were noted in the zone.