Limited field observations mean uncertainty is high.
Choose conservative terrain as we assess the snowpack after several weeks of prolonged cold temperatures and a significant amount of new snow and wind.
New snow and southerly wind may have formed reactive wind slabs in lee areas in the alpine and treeline.
Older hard slabs exist on all aspects from last week's northerly outflow winds. We expect these slabs to be quite stubborn to human triggering, but would be treating them with caution, as they overlie a weak layer of sugary facets.
Sunday Overnight: Snowfall easing. Strong southerly winds. Alpine temperatures rise to -10 C.
Monday: Snowing, up to 5 cm accumulation. Moderate to strong southerly winds. Alpine temperatures around -10 C.
Tuesday: Light snowfall. Moderate to strong southwest winds. Alpine temperatures around -8 C.
Wednesday: Partially cloudy, light flurries. Alpine temperatures around -12 C. Light southerly winds.
Last week, a natural avalanche cycle occurred in White Pass. This was a result of sustained north winds redistributing the 30-40cm of New Years Eve storm snow. This MIN from Wednesday describes widespread size 2 avalanches, running well into treeline. Avalanches also occurred further inland along the highway corridor on January 4.
Yesterday's 10-30 cm of new snow will continue to be redeposited by strong southerly winds into fresh wind slabs in the alpine and treeline. These new wind slabs overlie a heavily wind-affected surface of old harder wind slabs and sastrugi. The new snow will probably bond poorly to the old hard surface and human triggering might remain likely.
Below the new snow, many days of northerly outflow winds last week formed thick, hard slabs, that overlie a weak faceted (sugary) surface. These older hard slabs will probably be stubborn or unreactive to human triggering, but with limited observations in the past week, we would be treating them with caution.
