Regions
Vancouver Island.
Confidence
Moderate - Weather models in agreement as to timing, but type of precip (temp dependent) in question. Good field data on snowpack available.
Travel & Terrain Advice
Watch exposure during the warm parts of the day. In spring time, solar thawing and warmer temps will create wet surface instabilities faster than we expect and are used to as we emerge from winter. Even small loose wet sloughs have the force to push us into terrain traps and magnify potential injuries. Avoid travel and stopping above these traps, when exposed to large sun baked slopes in the heat of the day. These warm temps can also increase the fragility of cornices that grew over the winter. Be sure to give these overhangs a wide berth, while on top and when crossing below.A blast of storm/precip will take place Thursday, study what type of precip (snow, mixed precip or rain) falls at the different elevation bands (alpine, treeline and below treeline) and factor this into your decision making process as to what avalanche types you will expect to encounter (storm/wind slab if it snows vs. loose wet if it is mixed precip or rain).
Avalanche Summary
No new avalanche activity reported for the forecast region.
Snowpack Summary
Well unfortunately it seams like only the northern portion of the forecast region saw a significant amount of new snow over the past forecast period. The Cain region saw approx 16 mm of precip, west Strathcona saw around 8 mm and the east saw only 3 mm (rough conversion 1 mm of precip is approximately equal to 1 cm of snow if conditions (temps) permit). This new now sits on the previous moist storm snow which is bonding well to the old March 22 crust.
Snowpack Details
Surface: Moist new snow bonding well to previous storm snow. Upper: Moist prior storm snow well bonded to the March 22 crust. Mid: Well settled. Lower: Well settled.
Past Weather
Variable amounts of new snow (see snowpack summary), dependent on where you go in the forecast region. Winds were mainly light from the NW-SW. Temps were typical for what we expect in the spring time, cold overnight and warm (positive temps up into treeline elevations) during the day.
Weather Forecast
The forecast is for cloudy skies for this forecast period. A low pressure system will bring new precip to the area Thursday into Friday morning with the majority falling overnight. Strong SW winds will accompany the storm as well as a spike in freezing level at its climax. The type of precip that will fall and at what elevation will be the big question. Fingers crossed for snow!Wednesday: 0 to 4 mm of precip, winds light SW climbing to moderate, temps -4 to 0, freezing level 900 climbing to 1300 m.Thursday: 3 to 14 mm of precip, winds moderate SW climbing to strong, temps 0 to -1, freezing level 1000 to 1700 m.Friday: 0 to 6 mm of precip, winds moderate SW falling to light NW, temps 0 dropping to -2. freezing level 1300 to 260.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
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.