If Sunday's winds are stronger than forecast, the Avalanche Danger in the alpine may rise to Considerable. Watch for blowing snow at high elevations.
Summary
Confidence
Fair - Due to the number of field observations
Weather Forecast
On Sunday we can expect very light flurries, moderate northwesterly ridgetop winds, and alpine temperatures of about -18. Light snowfall is expected by Sunday night, and should continue until Tuesday as a pacific frontal system pushes eastward. With this system, we can expect strong westerly winds with freezing levels staying at valley bottom.
Avalanche Summary
No new avalanches have been reported, although I suspect there was some wind slab activity in response to Friday's wind event.
Snowpack Summary
Snow surfaces are variable with northerly, wind exposed aspects showing firm wind pressing, or a scoured exposed crust. More sheltered locations have up to 30 cm of low density, faceted snow. In the alpine and at treeline, strong northerly winds have transported this snow into stiff wind slabs on opposite slopes. Up to 70 cm below the surface you will likely find a hard, thick crust which formed mid-December. At higher elevations this crust has facets (sugary) snow above it and well-preserved surface hoar up to 10 mm in size in sheltered locations at treeline and below. Where the crust exists, it may be bridging triggers from penetrating to deeper persistent weaknesses. However, on high alpine slopes above where the rain crust formed, or in areas where rain didn't occur, deeply buried facets may still be susceptible to triggering, especially in thinner snowpack areas.
jlammers,
Avalanche Canada
