Avalanche Forecast

Issued: Feb 24th, 2016 8:10AM

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.

Rising temperatures and solar input may push the danger higher than forecast. Conservative terrain choices are essential with this complex snowpack. Give cornices a wide and respectful berth.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Thursday

Weather Forecast

The high pressure ridge currently over the Province will be with us for a few more days. The next Pacific system is forecast to arrive on the coast late Friday afternoon and cross into the interior early Saturday morning. Freezing levels are forecast to rise quite high on Thursday afternoon and into Friday. Some models are showing freezing levels to 300 metres. Winds are forecast to be generally light and from the south.

Avalanche Summary

One report of a wind slab avalanche from yesterday, size 1.5 S-SW aspect at 1800 metres. Loose wet avalanches are being reported, starting in steep terrain on solar aspects.

Snowpack Summary

A considerable amount of snow fell during the previous week, with the eastern part of the region receiving the largest amount of snow.. Moderate to strong south west winds redistributed the surface snow into wind slabs. For the most part, these wind slabs should be bonding with the storm snow on all but high elevation terrain. The storm slab is now sitting on the 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 reactive interface is a critical layer to watch in the region, and has been the active layer for some very large avalanches recently. 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

Wind slabs still exist on slopes previously loaded during the last storm and may be touchy in some locations

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The storm slab sitting on the mid feb melt freeze crust (possibly with facets) should be regarded as a serious problem, and will be for some time.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Cornices

Rising freezing levels in the next 2 days may make this problem worse.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 25th, 2016 2:00PM