Regions
Vancouver Island.
Explosive avalanche control results at Tree line on Mount Washington produced on North thru to West aspects numerous size 1 and a few size 1.5 and 2 all slab. No other observations or reports.
Past Weather
Cool temps, snowfall between 40 to 50 cm on the eastern edge of the island range and over 110 mm reported on the westerner leading edge of the range. Strong south wind persisted over the entire forecast region during the previous forecast period.
Weather Forecast
Out with the cold, here comes the warmth. As a more typical south western flow will be the predominate weather feature in our forecast region. Expect continued winter storms to deliver moderate precipitation amounts with above seasonal average freezing levels. Monday 20 mm of precipitation , Winds moderate to strong from the South east, Freezing levels 1400 meters. Tuesday 30 cm of snow , Winds moderate to strong from the South east, Freezing levels 1000 meters.Wednesday 30 cm of snow , Winds moderate to strong from the South east, Freezing level 100 meters.
Terrain Advice
Give Cornice features a large berth when travelling both below or above them.Cautious, Conservative and Selective terrain management must be practiced when entering Steep, Unsupported and Wind loaded features. Choose low angle terrain during storm events and avoid areas with overhead hazard.During periods of high hazard, travel in avalanche terrain is not recommended.
Snowpack Summary
50 cm of storm snow now covers a variety of surfaces and has been reported to be currently bonding moderately well. The new storm snow has been transported by the strong south winds and deposited this new storm snow on lee aspects (North) forming wind slab and building cornices. Temperatures have began to warm and new precipitation below 1400 meters is falling as rain creating an unconsolidated upper snow pack.The mid pack has a variety of melt freeze crust with one being extremely robust and having the ability to bridge the lower snow packThe lower snow pack is well settled and dense, with the exception of the alpine where a deep an nonreactive basal instability is possibly still lurking.
Snowpack Details
- Surface: A variety of surface conditions dependent on elevation and what form the precipitation fell as
- Upper: 50 centimeters of storm snow that is setting rapidly
- Mid: A variety of melt freeze crusts can be found with the possibility of buried surface hoar still being found.
- Lower: Well settled and dense, with the exception of the alpine where a deep an nonreactive basal instability is possibly still lurking.
Confidence
Moderate - forecast models agree on precipitation amounts, with some discrepancy as to how high the freezing levels may rise.
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.
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.
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.
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.