Avalanche Forecast

Issued: Feb 18th, 2019 4:40PM

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

kdevine, Avalanche Canada

Cariboos.

There is potential for humans to trigger avalanches, especially at lower elevations where a persistent weak layer exists. A cautious approach to backcountry travel is recommended.

Summary

Confidence

High -

Weather Forecast

MONDAY NIGHT - Clear with cloudy periods / southwest winds 10-20 km/h / alpine low temperature near -14TUESDAY - Mainly cloudy with isolated flurries, 2-4 cm / southwest winds 10-25 km/h / alpine high temperature near -10WEDNESDAY - Cloudy sunny periods and isolated flurries / north winds 10-20 km/h / alpine high temperature near -10THURSDAY - Mainly sunny with cloudy periods / northwest winds, 10-15 km/h / alpine high temperature near -13

Avalanche Summary

No new avalanches were reported on Sunday.On Saturday, a persistent slab avalanche was triggered by a skier on a north aspect on a 30 degree slope. Check out the MIN report here. These sorts of avalanches continue to be triggered by skiers and riders in the region. There was also evidence of large avalanches (up to size 3) that were triggered by strong wind in the north of the region. on Saturday.On Friday, two more small to large (size 1 to 2) persistent slab avalanches were triggered by humans. They were 50 to 70 cm deep and released on the mid-January surface hoar layer described in the Snowpack Summary. They occurred at treeline and alpine elevations on north to northwest aspects.

Snowpack Summary

Recent strong winds from variable directions, but most recently from the north, have blown around 5 to 10 cm of snow into wind slabs in exposed terrain.A touchy weak layer responsible for surprise avalanches and several close calls lies approximately 30 cm below the surface in shallow snowpack areas and 60 cm or more in deeper areas. This weak layer of surface hoar (feathery crystals) and facets (sugary snow) was buried in mid-January. On southerly aspects, the weak layer exists as a crust. This layer is most prevalent at treeline and below treeline elevations, but there have been a few reports of its presence in sheltered areas in the alpine. This layer is shallow enough to be triggered by humans, but deep enough to produce large avalanches.The lower snowpack is considered generally strong.

Problems

Persistent Slabs

Approximately 50 cm of snow sits above a persistent weak layer of surface hoar that was buried in mid-January. The surface hoar may sit on a melt-freeze crust on south aspects. This layer continues to be reactive to human triggering.

Avoid steep, open and/or sparsely treed slopes at and below treeline.Use conservative route selection, choose moderate angled terrain with low consequence.Be aware of the potential for wide propagation.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Wind Slabs

Most of the region has been hit hard by winds, which formed wind slabs in the lee of terrain features on a variety of aspects. If triggered, there is potential for a wind slab avalanche to step down to a buried persistent weak layer.

If triggered, wind slabs may step down to deeper layers and result in even larger avalanches.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Feb 19th, 2019 2:00PM