Avalanche Forecast

Issued: Mar 5th, 2014 7:44AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs and Persistent Slabs.

Peter, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Freezing levels are uncertain

Weather Forecast

Tonight and Thursday: Moderate to locally heavy snowfall – 5-15 cm overnight and another 10-25 cm during the day. The freezing level is around 1300-1500 m. Winds are moderate to strong from the SW. Friday: Mainly cloudy with flurries. The freezing level remains near 1500 m and winds are moderate from the W-SW. Friday night and Saturday: Moderate to heavy precipitation. The freezing level climbs to 1800 m and winds are strong from the SW.

Avalanche Summary

Several size 2-2.5 storm slab avalanches were reported in the Coquihalla on Tuesday. Most of these were from north to east aspects and likely released on the early March melt-freeze crust. A couple natural wind slab avalanches up to size 2 were also reported from the South Chilcotins.

Snowpack Summary

Coquihalla and south: Strong southerly winds have redistributed some of the new snow and formed wind slabs in exposed lee and cross-loaded terrain. Around 60 cm of storm snow has fallen in the past few days. This new snow may feel upside down due to warming temperatures, and seems to be bonding poorly to the early March melt-freeze crust. The mid February weak layer of crusts and facets, now down over 200 cm deep, has been reported to be rounding and bonding. Duffey Lake and north: New dense wind slabs are likely in exposed NW-E facing terrain and cross-loaded features. The early March melt-freeze crust is down 30-45 cm everywhere expect high north aspects. The mid Feb weak layer is generally down 60-120 cm depending on orientation to wind. Recent snowpack tests continue to give pops shears where this layer is less than 100 cm deep. Deeply buried weak layers of facets and depth hoar remain a concern on high alpine slopes with thin or variable snow cover.

Problems

Storm Slabs

Heavy snow, strong winds, and mild temperatures should work together to create fresh dense storm slabs, especially in wind exposed areas. All this new snow has been bonding poorly to the early March melt-freeze curst.

Avoid freshly wind loaded features.>Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

2 - 5

Persistent Slabs

This is probably more of a concern in northern sections where the mid February persistent weakness is buried less than a metre deep. Loading from new snow and wind could be enough to trigger this deeper problem.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Stick to simple terrain and be aware of what is above you at all times.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Mar 6th, 2014 2:00PM