Regions
Vancouver Island.
Limited observations due to poor visibility (foggy past few days) including during Tuesdays rain storm. One can, with a high level of certainly, expect widespread loose wet avalanche activity has occurred. When traveling in the hills keep a eye out for recent activity and factor that into your decisions.
Past Weather
Tuesday saw significant rain all the way to the top of the alpine with warm (positive temps) and high freezing levels 2500 to 3000 m
Weather Forecast
Get it while its good because it won't last long... Wednesday - Things cool off and some new snow arrives. 2 to 11 cm of new snow, winds strong SW drop to moderate SW, temps 0 dropping to -7, freezing levels 1200 down to 500 m. Thursday - More new snow early in the day. approx 10 more cm, winds light SW rising to strong S as the next warm wet storm approaches, temps -7 rising in the evening to +3, freezing level 500 up to 2000 m.Friday - Significant rain. approx 50 mm of rain forecast, winds moderate to strong SE, temps +2 to +1, freezing level 2000 dropping to 1300 m, so we might see the rain tapering into snow after the soaking and potentially very high summits will see all snow vs rain.
Terrain Advice
Study the bond of the new snow arriving Wednesday and Thursday to the old snow surface left after Tuesdays rain event and factor that into your decisions. Stay out of all avalanche terrain when the hazard rating is at high, during the forecast substantial rain event Thursday night into FridayLow avalanche hazard at below treeline, but many low snowpack hazards exist to keep an eye out for (open creeks, rocks, stumps..)
Snowpack Summary
Rain Tuesday saturated the upper snowpack. This moist snow will freeze as temps drop Wednesday and Thursday, reducing concerns around the weak layers found in the mid and lower snowpack. New snow Wednesday and Thursday, then another big rain event into Friday.
Snowpack Details
- Surface: Rain saturated from Tuesdays storm all the way to the top of the alpine
- Upper: Moist warm rain soaked snow (with forecast cooling temps Wed and Thurs, this layer should freeze up)
- Mid: Mainly settled with two suspect weak layers.
- Lower: Mainly settled and bridged, but a weakness near the ground from early season still exists.
Confidence
Moderate - Forecast weather models in agreement, but weather history spars due to many weather stations down.
Problems
Loose Wet
Loose Wet avalanches are the release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry Avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
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.