Avalanche Forecast

Issued: Mar 3rd, 2013 9:08AM

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

ghelgeson, Avalanche Canada

Cariboos.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Synopsis: The pineapple express is being replaced with a ridge of high pressure that should remain in place for the foreseeable future. A weak frontal wave makes it’s way inland Tuesday, but confidence in the exact timing and intensity are poor on Tuesday. Monday: Freezing level at 1000m. No significant precip. Increasing cloud cover. Light east wind.Tuesday: Freezing level around 600m. Light E/SE wind. Isolated flurries with no significant accumulation. Wednesday: Freezing level around 500m. Light S wind. No significant precipitation.

Avalanche Summary

Visibility has been limited, as a result there hasn't been much in the way of avalanche observations. A few natural size 3 avalanches in the north of the region were reported Saturday from SE facing slopes. With clear skies on Sunday, I imagine observations will increase.

Snowpack Summary

The Caribous picked up an extra 20 - 40 cm Saturday night which brings the recent storm total to 60 - 100cm. Strong winds out of both the SW and more recently NW have formed wind slabs on lee aspects in the alpine and wind exposed treeline elevations. The freezing level rose to around 1200m mid storm which has resulted in 4 cm of unfrozen schmoo/slush now buried by 25 cm of lighter density snow on many slopes below treeline. The Feb. 12 SH is now down 100 - 150 cm. This layer along with a deeper weak layer from late January continue to show planar failures when moderate to hard forces are applied in snow pack tests. These deeper layers have not been reactive to the weight of a rider as of late.

Problems

Storm Slabs

Human triggering remains a concern as the snowpack adjusts to it's new load. Storm slab avalanches have the potential to step down to the buried surface hoar resulting in large destructive avalanches.

Good day to make conservative terrain choices.>Avoid being on or underneath sun exposed slopes when the solar radiation is strong.>The new snow will require another day or two to settle out and stabilize.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 6

Cornices

The storm has left many large cornices in it's wake on lee slopes, many of which may be teetering on the brink of failure. Cornice fall has the potential to initiate large destructive avalanches.

Extra caution needed around cornices with current conditions.>Avoid slopes with overhanging cornice.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

A weak layer of surface hoar and/or a crust is now down 100 - 150 cm. The coming days will reveal more about the sensitivity of this layer, but it's still suspect at the present time.

Be wary of paths that have not avalanched recently.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 7

Valid until: Mar 4th, 2013 2:00PM