Heavy rainfall at all elevations Thursday night and Friday is expected to make travel conditions rather miserable, and may induce a round of natural avalanche activity.
Confidence
Low - Timing, track, or intensity of incoming weather system is uncertain on Friday
Weather Forecast
Friday looks to be a pretty funky meteorological period. The good news is that we are expected to return to a more typical stormy winter pattern. The bad news is that we have to endure some rain, perhaps even some freezing rain, before we get back to the snow on Saturday. THURSDAY NIGHT: Freezing level around 2500 m, moderate to strong south/southwest wind, 20 to 30 mm of precipitation expected.FRIDAY: Overcast, freezing level around 1900 m, moderate to strong south/southwest wind, 30 to 45 mm of precipitation expected.SATURDAY: Overcast, freezing level around 1200 m lowering to 700 m in the afternoon, light south/southeast wind, 2 to 4 mm of precipitation expected.SUNDAY: Scattered cloud, freezing level around 700 m, light south/southeast wind, 4 to 8 mm of precipitation expected.
Avalanche Summary
No new avalanche activity has been reported recently, but heavy rain forecast for Thursday night and Friday may induce a round of natural avalanche activity.
Snowpack Summary
Two successive storms produced 40 to 80 cm of snow late last week. This week temperatures warmed dramatically. On Wednesday the Deeks Peak weather station (1280 m) got up to +8.7 C, Mt. Strachan (1220 m) topped out at +11.4 C. These warm temperatures combined with last Friday night's rain event have allowed the entire snowpack to settle and stabilize, but heavy rainfall could induce a round of natural avalanche activity. 50 to 100 cm below the surface there are a few prominent melt-freeze crusts that were buried mid-December. This layer has not produced much in the way of avalanche activity and is likely trending towards dormancy. Beneath the mid-December crust, the lower snowpack is generally strong and well settled.The snowpack depth is about 160 cm at 1000 m, 220 cm at 1250 m. Many early season hazards are still present at lower elevations.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.