Steamboat & Flat Tops
SnowpackCMC AIARE Lvl 1 · Jan 19, 2019 · Steamboat & Flat Tops
Weather
Broken skies early on in the day that quickly moved to overcast, temps in the low 20's all afternoon with calm to light winds on the west summit. Significant coating of rime ice on all trees on the drive up the pass. No snow transport observed with the new snow. Snow surface of today was predominantly stellar crystals with very little indication of wind effect like the snow surface on Friday had.
Snowpack
Dug several pits in the meadow on slopes that faced south and had minimal slope angle (15-20 degrees) at 9500ft. Height of snow was 190-220cms, height of new snow was 35-40cms. We were able to view and verify the existence of storm slab and persistent slab problems at this location. Storm slab was failing consistently in the medium loading steps in our CTs (four CTs failed in medium range @ 35-40cms down) all resistant planar. We also had a mix of CTs failing at a crust/facet layer down 70-80cms (CTEx2, CTMx4, and CTHx3) all sudden planar. We ran several ECTs and they did propagate on the crust/facet layer (ECTP 25 down 70cms) but did not propagate on the storm slab layer (ECTN16 down 35cms). Frequent whumphs were felt in and around our pits. Standing above pits to fill them in would trigger failures in the crust/facet layer that easily propagated between pits. We attempted to trigger steep convexities in old gravel pit but no surface cracks were visible despite a wide collapse/whumph. Steep road cuts on the drive up did not show any natural activity.