Regions
Northwest Inland.
Confidence
Fair - Due to limited field observations
Weather Forecast
Synopsis: The first in a series of frontal systems will reach the coast on Thursday afternoon spreading light to moderate precipitation to the Northwest through Saturday morning.Thursday: Increasing cloud with light snow developing in the evening. The freezing level rises to 1500 m during the day and winds are generally light from the southwest. Friday: Moderate precipitation – 5-15 cm. The freezing level is near 1200 m and winds are moderate from the south. Saturday: Light precipitation continues. The freezing level remains around 1200 m.
Avalanche Summary
Solar induced avalanche activity tapered off on Tuesday as temperatures cooled. Recent activity included loose wet sluff on sun-exposed slopes, and isolated cornice falls and glide slab releases on steep open slopes below treeline.
Snowpack Summary
Surface snow has settled with the influence of warm temperatures and surface faceting continues on steep shaded alpine slopes. Solar aspects at all elevations and all lower elevation terrain are now well into a daily melt-freeze cycle with sun-exposed slopes becoming very weak with daytime warming. 30 - 60 cm of snow overlies a crust, old wind slabs or surface hoar layer buried on March 9th. The distribution of the surface hoar is also highly variable and it does not exist in every drainage. I would still remain cautious and continue to dig and test before diving into my line. Deeper in the snowpack, basal facets may resurface as a concern with continued mild temperatures.Cornices have become well-developed and could easily become unstable during periods of warm weather or direct solar radiation.
Problems
Cornices
Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.