Avalanche Forecast

Issued: Feb 25th, 2016 8:06AM

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

bcorrigan, Avalanche Canada

Kootenay Boundary.

High temperatures and solar warming are driving the hazard ratings at this time. Conservative route selection and cornice avoidance are the theme for the next few days.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

A weak front will move onto the coast Friday night bringing light precipitation to the coast ranges and spotty precipitation to the Interior on Saturday. A stronger front will move onto the coast late Saturday through Sunday bringing light precipitation to the interior. On Sunday another pulse of moisture will pass through the region bringing 5 to 10cm of snow at higher elevations. Freezing levels will rise to near 2500 metres across the south on Friday but should begin to fall on Saturday.

Avalanche Summary

Reports of avalanche activity have slowed down in the region, but sluffing has been reported in steep north facing terrain and a size 2.5 avalanche, N. aspect, appears to have ben triggered recently by sledders. Loose wet avalanches are being reported, starting in steep terrain on solar aspects.

Snowpack Summary

There is now a complex snow pack in the region. Wind slabs still exist in lee terrain and may be problematic at high elevation on north and east aspects. The storm slab is now sitting on a melt-freeze crust that formed during the 2nd week of February and has been reported at various levels from 50 to 100cm throughout the region. This crust is widespread and may co-exist with surface hoar or weak facets. This interface is a critical layer to watch in the region, although it now appears to be bonding with the layers above and below it. A large trigger, such as cornice failure, or perhaps a wind slab avalanche could make this layer react and create a large, destructive avalanche. Warm temperatures may also make this layer reactive. Buried surface hoar from January is still being reported throughout the region and noted as a serious layer below 1800m. Surface hoar growing up to 8mm has been reported in the past few days. Sun crust may exist on solar aspects at the surface and has also been reported in the region 20cm below the surface. Daytime heating will help settle the snowpack but could also make for touchy conditions on south facing slopes in the afternoon.

Problems

Wind Slabs

Reactive wind slab slabs may still be found in high, north east facing terrain

Avoid cross loaded slopes at or above treeline.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The slab overlying the mid-Feb melt freeze crust varies from 40 to 100cm through the region. This is still a layer to keep in mind, as an avalanche on this layer could be large and destructive.

Use conservative route selection, stick to moderate angled terrain with low consequence.>Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Cornices

Cornices are large and fragile in the region. Daytime warming with high freezing levels will only make them more prone to collapse.

Cornices become weak with daytime heating. >Extra caution needed around cornices with current conditions.>Do not travel on slopes that are exposed to cornices overhead.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 26th, 2016 2:00PM