Avalanche Forecast

Issued: Mar 4th, 2018 4:23PM

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

mbender, Avalanche Canada

Cariboos.

Although the temperature is forecast to remain cool at upper elevations, when the sun does come out it can have an immediate impact on those slopes directly facing it.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

MONDAY: Mix of sun, cloud and isolated flurries / Light to moderate west wind / Alpine temperature -14 TUESDAY: Mix of sun, cloud and isolated flurries / Light to moderate west wind / Alpine temperature -15 WEDNESDAY: Mix of sun, cloud and isolated flurries / Light southwest wind / Alpine temperature -10

Avalanche Summary

Recent avalanche activity in the past 3 days has consisted of mainly natural wind and storm slabs to size 1.5 and 2 in the alpine and tree line on south facing and northeast facing slopes. There was however a report from the western portion of the region of a natural size 3.5 deep persistent avalanche approximately 200cm deep on a west aspect starting in the alpine at 2300m running down to 1400m. This was reported to have run in the past 48 hours.

Snowpack Summary

Up to 60 cm of recent storm snow is settling and has been redistributed into slabs in wind-exposed terrain. Below this is a layer buried mid-February that presents as a sun crust on solar aspects, and spotty surface hoar on sheltered slopes. This layer looks most concerning on on solar aspects where it's associated with with small facets or surface hoar above.There are several deeper layers in the mid-pack that have shown signs of improving but remain on the radar as a low probability to trigger, yet would produce a high consequence avalanche if triggered. We are talking about surface hoar buried back in December and January. Near the base of the snowpack is a November crust combined with loose sugary snow. These layers may "wake-up" with strong inputs such as sustained warming, sustained snowfall, large triggers (e.g. cornice fall, smaller avalanches coming down from above); human triggering is also possible in shallow snowpack areas with variable snow depth and convoluted terrain.

Problems

Wind Slabs

Recent new snow combined with wind has promoted slab development on lee slopes in wind exposed areas.

Be cautious as you transition into wind affected terrain.Give cornices a wide berth when travelling on or below ridges.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Persistent Slabs

Buried weak layers exist within the snowpack and may be reactive intense solar radiation or to large triggers such as a cornice fall. Human triggering may also be possible in shallow or thin, rocky, unsupported terrain.

Watch convoluted terrain with variable snowpack depth and multiple trigger points.Pay attention to overhead hazards like cornices which could trigger persistent slabs.Carefully assess and consider avoiding southerly facing slopes

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3.5

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