Avalanche Forecast

Issued: Jan 4th, 2018 5:11PM

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

mbender, Avalanche Canada

Lizard-Flathead.

Expect to continue to see persistent slab avalanche activity as the snow sitting above the persistent weak layer further settles and consolidates with forecast warmer temperatures. Adopt a conservative approach in the coming days.

Summary

Confidence

Moderate - Freezing levels are uncertain on Friday

Weather Forecast

FRIDAY: Cloudy with isolated flurries, accumulation 3-5cm / Light southwest wind / Alpine temperature -3 SATURDAY: Cloudy with isolated flurries and sunny breaks / Light to moderate southwest wind / Alpine temperature -4 SUNDAY: Cloudy with flurries / Light to moderate west wind / Alpine temperature -5

Avalanche Summary

On Thursday there was a report of skier triggered avalanche in Orca bowl involving a group of 11 with 6 people caught and partially buried. This was a size 2 avalanche occurring on a northeast aspect at 1975m and reportedly running as a windslab sitting on a crust. Additionally there have been several natural avalanches between 1600m and 1800m on steep or open glades on all aspects. This is where the mid-December layer has been most active.

Snowpack Summary

A persistent weak layer buried mid-December is buried 40-70 cm below the surface. This layer can be found in a variety of locations, but most commonly can be found between 1600m and 1800m and consists of crusts on south and west facing slopes and feathery surface hoar in sheltered areas at and below tree line. It has been producing sudden results in recent snowpack tests.At higher elevations, wind has modified the snow pack creating a stiffer snow on top of softer snow condition. The lower snowpack is generally well settled with a thick prominent crust that was buried near the end of November. This crust has been reported to be unreactive, however it is possible that it may have been the bed surface for a skier triggered avalanche that happened on Thursday (See Avalanche Activity section below for details).

Problems

Persistent Slabs

A weak layer composed of surface hoar and/or crusts is buried 40-70 cm below the surface. This layer continues to reactive.

Watch for whumpfing, hollow sounds, and shooting cracks.Choose supported slopes without convexities at treeline where buried surface hoar may be preservedAvoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Moderate winds have created fresh wind slabs in the alpine.

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 5th, 2018 2:00PM