June Backcountry

We traversed multiple aspects in the June Backcountry to track warming and test wind slabs.

Stability:

•  We saw small natural rollerballs near and below treeline on east and southeast slopes.  We intentionally triggered three small wet loose avalanches on an east aspect at 9700 before 11 am. We got isolated, local cracking in wind slabs. We saw very small natural and skier-triggered dry loose sluffs on northerly slopes near and above treeline. There were many tracks on north, northeast, east, and southeast aspects at all elevations, with not much more than small and isolated sluffs as the only signs of instability.

Snowpack:

• Wind slabs were up to 50 cm thick soft slabs not propagating in ECTs (see snowpack photo). The top 5 cm transitioned from dry snow to moist on solar aspects near and below treeline. There was a short window before the surface refroze into a 1 cm thick crust. There is a thick, hard melt-freeze crust under most recent storm snow down 5-15 cm on windward aspects, down 30-55 cm on east to north aspects.

Very small natural and triggered dry loose avalanches near and above treeline on northerly aspects with cold snow. Small, intentionally triggered wet loose avalanches on an east-facing near treeline test slope just before 11 am. Isolated and localized cracking in soft wind slabs. We saw a wind slab avalanche that likely failed in the past 2 days above treeline on a northeast aspect of San Joaquin ridge.