Strong wind from the south and west formed wind slabs. The recent snow sits on firm old surfaces and might need more time to stabilize. Assess the snowpack carefully when transitioning into wind affected terrain.
Strong south and westerly wind formed fresh wind slabs on Sunday. Wind slabs will be found below ridge crests and in lee terrain features. The strong wind might have built slabs farther down slope than expected.
Sunday night: Clear, trace of new snow, moderate north wind, alpine low -12 °C, freezing level at valley bottom.
Monday: Mainly sunny with a few clouds, moderate northeast wind, alpine high -10 °C, freezing level at valley bottom.
Tuesday: Sunny, moderate northeast wind, alpine high -8 °C, freezing level at valley bottom.
Wednesday: Mix of sun and clouds, moderate west wind, alpine high -5 °C, freezing level at valley bottom.
Skiers were surprised by wind slab avalanches on north and northeast aspects in the White Pass area on Friday. The slabs were about 20 cm thick and the avalanches reached up to size 2. Slabs were still reactive to skier traffic on Saturday.
30-40 cm of recent snow are sitting on old firm surfaces. Strong wind from the south and west transported the snow and formed fresh wind slabs. The bond between the recent snow and the old firm surfaces was reactive to skier traffic in the last couple days. On steep, south aspects at treeline and below, there is potential for the existence of a thin sun crust.
The lower snowpack is well bridged by the layers above, and it is unlikely that avalanches will be triggered on weak, sugary crystals near the ground at this time.
