Mild temperatures may increase the reactivity of recently formed wind slabs as the storm snow continues to settle. Watch for new wind slab formation on Thursday afternoon as the wind speed is forecast to become strong again.
Ongoing moderate to strong southerly winds have redistributed the recent storm snow into reactive wind slabs in exposed terrain. These slabs may overlie a weak interface and could remain reactive longer than normal.
A ridge of high pressure brings dry and sunny conditions for Thursday before a weak storm system arrives Thursday night.
Wednesday Overnight: Partly cloudy, moderate SW wind, treeline temperature around -8 °C.
Thursday: A mix of sun and cloud, moderate S wind becoming strong in the afternoon, treeline high around -6 °C.
Thursday night and Friday: Snowfall 10-20 cm, strong S wind, treeline high around -2 °C.
Saturday: A mix of sun and cloud, moderate SW wind, treeline high around -4 °C.
On Tuesday, the Avalanche Canada field team was able to ski cut reactive wind slabs on steep north aspects at upper treeline. Their MIN report has a great photo of a skier triggered avalanche on a small test slope. With ongoing moderate SW wind and mild temperatures continuing, wind slabs are expected to remain reactive to human triggering on Thursday and new wind slab formation is expected as the wind speed increases on Thursday afternoon.
30-50cm of recent storm snow overlies very firm surfaces in White Pass. This storm snow is settling rapidly with warm temperatures but was found to be unreactive to skier traffic on Wednesday by the field team. South winds have likely formed new wind slabs on lee features in the alpine. In open wind exposed terrain at treeline, a spotty rime crust was reported on Wednesday. Riding quality has been improving since the extreme wind event but thinly buried hazards still exist in exposed areas. These hazards include rocks and waves of sastrugi. Check out the recent MIN post from the field team for more details on recent the snow conditions.
