Vancouver Island Avalanche Bulletin

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

Confidence: Good. Freezing levels and day time temperatures will be the chief thing to watch.

 Main Concerns:

• Wind Slabs and fresh redeposited Wind Slabs, isolated in Alpine & Tree Line East, North, North West
• Cornice Fall  (natural trigger)
• Solar or Steep slopes, wet surface slides (natural trigger) 

Weather:

Since Friday The Island Alps received flurries sunny breaks giving another 10 to 20 cm snow and some clear breaks with above freezing temperatures and then cool temps in the eves and winds that were moderate at ridge top from the South East, South and West.

The outlook the start week is mostly clear with possible PM flurries into Wed, should be all cold nights and day time freezing levels rising a little higher each day to 1750m on the South and East Island 1500 m North Isle.  Light to Moderate winds starting from East and South and moving through the week to West and then North or North West by Wed.

Avalanche Activity:

Thaw cycle activity is occurring. Steep ground natural slough triggered size 2 slab in alluvial fan. Suspect some cornice falls and resulting wind slab triggered as well as point release wet and dry.

Snowpack:

At lower elevations a Melt freeze crust is faceting over night and gaining surface hoar. North and cold slopes in the Alpine are still soft but gaining a temperature crust below 1500m.  Solar aspects are consolidating fast and steeper terrain is shedding and pin wheeling. Most of last weeks' snow is somewhat up side down due to temperature and or wind. Expect surface hoar development.

The old snow layers from January and February are no longer much of a concern as they gained rain and then refroze in March. Our concerns today are more typical for the Coast; storm snow and windslabs with over developed cornices and snow plastered on some steeper slopes.  The depth and consistency of the windslabs varies quite a bit due to the extreme and changeable winds; 25 cm and quite stiff cross loaded slabs to 1.5 meter deep wind slabs with softer and stiffer layers providing some shears in the  moderate to hard  range closer to the surface. Most of the upper snowpack is settling and bonding fairly well deeper down.

In the worse case right now a cornice drops and triggers a large slope into the first wind slab which then steps down to the other older slabs above the crusts. This could be up to 3 meters deep but not likley with out warming or more load...

Travel advisory:

Monday: Human Triggering is Probable to Possible in the Alpine and improving for Tuesday except Solar aspects. 

  Monday, Tuesday and Wednesday Natural Triggering is Probable as Loose snow instabilities and cornices may fail with warming or sun.  Localized Wind Slab on Lee and Cross-loaded slopes exist on East through North through W aspects at and above Tree Line. Wide spread Cornice formation exists NW through East and is very acutely formed at this time.. The thinner wind zone crossloaded features are likely to be more sensitive to human triggering as are steeper slopes and stress points or convex areas. By Wednesday Human Triggering may be Possible to Unlikely.

Outlook: