Avalanche Forecast

Issued: Jan 8th, 2012 3:00PM

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

Avalanche Canada ghelgeson, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

The warm front associated with the weekend storm has delivered surprisingly little precipitation to the So. Columbias. The ridge that has been keeping the precip out slides to the south Sunday night allowing a cold front to impact the area Monday. I expect 5 - 20 cm out of this wave with the western parts of the region receiving the higher precip amounts. Winds will switch from the W to NW late in the day Monday with enough oomph to create yet another round of windslab avalanche activity. Expect 1500 m temps to be near 0 C. A ridge of high pressure moves in Tuesday which should break up the cloud cover and provide some good visibility.

Avalanche Summary

A few different natural avalanches involving windloaded pockets were reported from the alpine yesterday. Avalanches averaged size 2, featuring crowns 30 - 40 cm in depth.

Snowpack Summary

The region has received 30 - 70 cm of snow out of the latest storms. This new snow has been redistributed into wind slabs at both treeline & alpine elevations. Slopes facing N, NE & E are immediately lee to the recent SW winds, so the biggest stiffest wind slabs will be found on those slopes. Slopes facing NW & SE are likely crossloaded. There are currently three different surface hoar layers in play. Moving from top to bottom, the first one is the January 3rd SH which is being reported from many different locations, down 30 - 70 cm below the snow surface. The next one is the December 24 SH buried 60 -90 cm below the surface. The last one is the December 11th SH buried 100 - 150 cm below the surface. Test results continue to show sudden planer results on this layer with hard triggers. It's been the most sensitive on south through east facing slopes around the treeline vegetation band, but it is present on all aspects. The last significant layer in our snowpack is a rain/temperature crust that can be found from valley bottom up to about 1600m. This crust could be a bed-surface below treeline in the future.

Problems

Wind Slabs

An icon showing Wind Slabs
Hard slabs capable of wide propagation exist. These slabs are likely to break above you. Winds switch from SW to NW Monday, so, you need to carefully evaluate each slope for windslab hazard.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 5

Persistent Slabs

An icon showing Persistent Slabs
A deep slab rests on a touchy surface hoar weakness buried in mid-December. This layer is still sensitive and susceptible to rider triggered avalanches which will likely be large, destructive and may fracture across surprisingly far distances.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

4 - 8

Valid until: Jan 9th, 2012 8:00AM