Vancouver Island Avalanche Bulletin

Valid until Wednesday February 15th 2012

Next update Wednesday Feb 15th 2012

Confidence:  Good. But watch freezing levels during the day time if sunny.  Always check local conditions.

Main Concerns: (Avalanche problems)

Storm Slab/Crust Slab - in the Alpine on cooler aspects. Human triggering is possible on steeper unsupported terrain. The avalanche size is small.

Wind Slab - In the Alpine reverse loaded Wind Slab may form over Monday Tuesday. South SE E aspects. Triggering is always easier when the slab is thinner. Avalanche size small.

Weather: Over the weekend it dried out and cooled down. 5 to 9 mm of precipitation fell as light rain at lower elevations Saturday and cooler temps saw light snow in all areas Sunday. The Winds just barely moved snow from the SSE Sunday.  The outlook:  A clearing and cooling trend for the early week is interrupted Tuesday with light snow in all areas, giving 6 to 10 cm depending on convection and local weather. The Winds are light Monday West and switch to North up to Moderate Tuesday and switch again Wednesday to NW or West and back off to light again. Freezing levels Monday at 800m rising a bit with the sun and cooling over night and into Tuesday 700m day time and 300m overnight. Wednesday the temps rise with clearing & sun to near 1000m before cooling right off again for the night.

Snow Pack:

Alpine: 10 to 20cm of 48 hour snow sit on a weak crust, under the crust are moist facets/mixed forms producing clean easy shears, below that is stronger crust down 60cm that produces shears with hard results(breaking the crust first). One old storm layer has a shear that is producing smooth shears down 70cm plus with really hard forces required to get results. The December crust is well buried in most locations; but in shallow or steep start zones it may be quite close to the surface... The Lower snowpack is strong and well consolidated.

Treeline & Below Treeline: Two layers of crusts cap off the upper snowpack. The upper crust is breakable and the foot pen is from 0 to 25 cm. On cooler aspects if you break the crust it produces propagation cracks and shears easily in unsupported ski cuts, RB 3 results, about 10 cm deep in what I am calling a 'Crust Slab'. At Treeline the same old storm weak layer is also producing hard but clean shears down 55 or 60 cm. Thin snowpack areas are wet and rotten and should be avoided, foot pen was up to 70 cm in those areas.

Surface condition outlook: Expect the crust near surface to become weaker and more brittle during the week, especially on colder aspects; as the cold air temps and warm slush temps under the crust will produce a weaker crust and sugary faceted grains. Expect also surface hoar to develop over nights and persist in cooler and shaded aspects and higher elevations.

Glide cracks were showing up on convex rolls at lower elevations.

East Island snow packs are about 2.2 m average at Tree Line. West Island snowpack are about 3.5 m average and North Island snow pack is about 2 m average.

Avalanche Activity:

None reported. Old debris litter many tracks and run outs from the wet loose cycles last week.

Travel Advisory: 

• Breakable crust will become more breakable on cold aspects and higher elevations during the week.
• Pay attention to overhead hazards like cornices, give them a wide berth whether you are above or below them.  The possibility of a cornice drop is more likely with the recent weather and could trigger larger avalanches that might propagate laterally into adjacent terrain.
• Be cautious as you transition into wind affected terrain and note new wind slab may be backwards loaded from North NW winds on Tuesday and Wednesday loading East through SW aspects.
• Storm Slab/Crust Slab hazard could exist on slopes steeper than 35 degrees but only at higher elevations.
  
• Watch for puddles and weak creek or drainage snow coverage.

'Normal Caution' is advised. Watch for unsure footing slip and fall or crusts breaking away underfoot.

Prepared by Niko Weis