Wind slabs can be found in leeward areas near ridge crests, while wet or moist snow is a concern on sunny and lower elevations slopes. Also be wary of large cornices that can weaken with warming.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
TONIGHT: Mostly cloudy, flurries. Accumulation 2-6 cm. Ridge wind light to moderate, west. Alpine temperature near -6. Freezing level 500 m.FRIDAY: Increasing cloud and flurries. Accumulation trace. Ridge wind strong to extreme, southwest. Alpine temperature near -5. Freezing level 1600 m. Flurries overnight.SATURDAY: Mostly cloudy, flurries. Accumulation 5-10 cm. Ridge wind light to moderate, southwest. Alpine temperature near -5. Freezing level 1500 m.SUNDAY: Mostly cloudy, flurries ending. Accumulation 2-6 cm. Ridge wind light, southeast. Alpine temperature near -5. Freezing level 1500 m.
Avalanche Summary
Wednesday there was a report of natural cornice failure that resulted in a size 2.5 wind slab release on a northeast aspect at 2700 m, while a skier was able to trigger a size 2 wind slab (40 cm deep and 100 m wide) on a recently buried crust on a similar aspect at 2400 m. There was also a report of a remotely triggered (from a distance) size 1 wind slab in an east-facing gully at 2300 m.On Tuesday a natural size 2.5 cornice failure on a north facing alpine feature did not produce any additional avalanche activity when it impacted the steep slope below. In a different location a skier intentionally trimmed a cornice so that it would fall onto a north facing slope at 2500 m. When the small piece of cornice impacted the slope it triggered a size 1.5 wind slab avalanche 30 cm in depth. A natural size 2.5 wind slab was observed on a cross-loaded east facing feature at 2400 m too.On Monday steep solar aspects produced natural loose wet avalanches to size 2 between 2000 and 2600 m. A size 3 natural cornice failure was also reported from a north facing slope at 2600 m.Natural loose wet avalanches to size 2 were widespread on all aspects last Sunday.
Snowpack Summary
A thin surface crust is now present on all aspects to at least 2000 m. This crust likely goes even higher on south facing aspects, while 10-25 cm of cold snow can still be found on high elevation northerly facing aspects. There are now a few different crusts in the upper 50 cm of the snowpack, with only the most recently buried crust posing a concern in wind-loaded areas.There is some lingering concern around the mid-March Persistent Weak Layer (PWL) in the alpine where it is found 60 to 100 cm below the surface. This buried crust/surface hoar interface was widely reactive last week, but has not produced any avalanche activity in the last few days. It is likely trending towards dormancy, but we need to keep it in the back of our minds as it is capable of producing large avalanches should it be triggered (think step-down from a surface avalanche or a cornice collapse).Deeper persistent weak layers from December and January are dormant at this time.
jmcbride,
Avalanche Canada
