Avalanche Forecast

Issued: Feb 24th, 2019 4:24PM

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.

jsmith, Avalanche Canada

Cariboos.

A persistent weak layer that has been most pronounced at lower elevations has created a low likelihood, high consequence scenario that requires discipline and careful terrain selection to manage effectively.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

SUNDAY NIGHT: Clear / light, northeasterly winds / Alpine low -19.MONDAY: Sunny / light, northeasterly winds / Alpine high -12.TUESDAY: Sunny / light, northeasterly winds / Alpine high -10.WEDNESDAY: Sunny / light to moderate, northeasterly winds / Alpine high -5.

Avalanche Summary

On February 16th, 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 kinds of avalanches have become less frequent, but they are still possible to human trigger in specific locations and the consequences can be high.

Snowpack Summary

Up to 5 cm of recent new snow fell with moderate to strong southwest winds. The new snow sits on top of approximately 10-30 cm of low density snow in some areas, and wind slabs in other areas. A weak layer that was buried in mid January is down 30-60 cm. This layer consists of surface hoar (weak, feathery crystals) and facets (sugary snow). The layer also likely consists of a crust on south facing slopes. Avalanche activity on this layer has slowed, but test results, and recent observations of whumphing still indicate that this layer may still be possible for humans to trigger in specific locations. It has been most reactive at treeline and below treeline.The lower snowpack is generally considered to be strong, except for shallow, rocky areas where the cold temperatures continue to facet (weaken) the snowpack.

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 crust on south aspects.

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

Unlikely - Possible

Expected Size

1.5 - 2.5

Wind Slabs

Buried wind slabs that are sitting on facets (weak, sugary snow) in rocky alpine terrain may remain reactive to human triggers longer than is typical for this region.

Avoid slopes that sound hollow or drum-like.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Steep and rocky terrain are likely places to trigger buried wind slabs.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 25th, 2019 2:00PM