Vancouver Island Avalanche Bulletin

Valid until March 21.

DANGER RATINGS (Make sure you understand the danger level meanings)

Below Treeline areas especially on the East slopes of the Island are becoming below threshold for avalanches. 

Confidence: Fair as extent of thaw cycle not fully observed & precipitation amounts for Sunday on N. Island vary with current weather models. North Island could spike to HIGH Hazard if rain amounts are over 10 mm.

Main Concerns:

• Thaw instabilities affecting  cornices and surfaces
• Old crusts under recent storm loaded wind slabs
• Rain soaked bonds at or below crusts

Weather:

The past weekend storms brought heavy snow 60 to 110 cm, but this all ended Tuesday with 10 to 20mm rain to 1400 - 1700 m. Dryer weather and cooler nights capped off the week.

Clear and Dry for the forecast period until Sunday when clouds and showers are possible,  more precipitation in the form of rain possible for the North Island Sunday. Freezing levels near surface over night and rising to 1750 m East Island and 2000 m West Island rising even further by Saturday during the day. Winds light North through North West switching to Light to Moderate Southerly Sunday.

Avalanche Activity:

Little reported. Expect natural surface sloughs and perhaps cornice or pillows to release. Main natural cycle ended last Tuesday.

Snowpack:

Thaw instabilities of past storm snow and over head cornice or steep angled snow will be one of the main concerns over the forecast period. Below 1400m widespread rain crust sits over most surfaces on the island. The weekend storm snow varies from very little on South Aspects, to 60 plus cm on average and 150 cm in wind deposited areas. New wind slabs were formed on many aspects at higher elevations and may still be reactive to human triggering. Prior to the warming the Cross loaded and thinner East and West aspects in the Wind Zone were most reactive over faceted and potentially collapsing crusts. Old Wind slabs are also buried under the storm snow over suspect crusts. Strong Northerly winds on the 7th and 8th scoured much of the crust/ facets off North slopes and destroyed most surface hoar.  Rain soaked snow added considerable load to the new snow and in some areas perked down to crusts down 60 in the old snow.

Terrain Discussion: Stay out from under big steep slopes and cornices

Travel Advisory:  Serious caution is advised with warming and thaw. During day warming and on Solar aspects expect over head hazards of cornice or over angle terrain to shed what could be a lot of snow, this could trigger deeper instabilities.  Human triggered avalanches are still possible especially at higher elevations.  Don,t trust the crusts as some may collapse or shear with human loads. Time your trips early in the day as the forecast temps could re awaken the deeper layers as the snow looses strength with the heat.

Outlook:

Clear skys with freezing nights and warm/hot days, changing to Clouds and possible light rain further North by Sunday