Avalanche Forecast

Issued: Feb 25th, 2019 4:08PM

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.

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

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

MONDAY NIGHT: Clear / Light to moderate, northeasterly winds / Alpine low -20.TUESDAY: Sunny / Light, northeasterly winds / Alpine high -10.WEDNESDAY: Sunny / Light, northeasterly winds / Alpine high -8.THURSDAY: Sunny / Light, northerly winds / Alpine high -9.

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. These buried wind slabs are sitting on facets (sugary snow) which may cause them to remain reactive to human triggers longer than what is typical for this region.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. 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 (weak, feathery crystals) that was buried in mid-January. This layer has created a low likelihood, high consequence scenario.

Avoid low elevation cut-blocks where this layer is well preserved.Use conservative route selection, choose moderate angled terrain with low consequence.Avoid steep, open and/or sparsely treed slopes at and below treeline.

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.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 26th, 2019 2:00PM