Avalanche Forecast

Issued: Mar 30th, 2016 9:37AM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Cornices, Loose Wet and Persistent Slabs.

triley, Avalanche Canada

Cariboos.

Special Public Avalanche Warning for this region. Forecast very warm temperatures, high freezing levels, and strong solar radiation will increase the avalanche danger to HIGH in the alpine during the hottest part of the day.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

A well-developed ridge of high pressure will continue to provide clear skies, light winds, and very warm temperatures for Thursday and Friday. Freezing levels may climb as high as 3000 metres, and there may not be a freeze on Friday morning in some areas. A weak trough will move inland from the coast on Saturday, bringing moderate southwest winds and increasing cloud cover. Some light precipitation may make it into the Interior ranges, however it may be mostly rain as the freezing level should remain at about 2500 metres on Saturday.

Avalanche Summary

On Tuesday numerous natural cornice releases resulted in avalanches up to size 3.0 from various aspects in the alpine. On Monday we had reports of several natural cornice falls up to size 2.0 from various aspects in the alpine. There were also several loose moist or wet avalanches up to size 2.0 on solar exposed aspects in steep terrain in the late afternoon.

Snowpack Summary

New surface crusts have developed at all elevations on solar aspects and on all but high alpine elevations on shaded aspects. Thin surface crusts may break down early with continued warm temperatures. Approximately 30-50 cm of settled storm snow sits on a melt-freeze crust buried on Mar. 20. The late February persistent weak layer continues to be a concern for wide propagations in isolated terrain, however it may take a large trigger like a cornice fall to initiate an avalanche. Watch for recent storm snow releasing as loose wet avalanches on steep solar aspects with strong solar radiation and daytime warming this week.

Problems

Cornices

Continued high freezing levels and very warm daytime temperatures are very likely to result in natural cornice falls. Large cornice falls may trigger buried weak layers resulting in very large avalanches.

Avoid steep slopes below cornices.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Loose Wet

Forecast high freezing levels and very warm daytime temperatures may break down surface crusts early and result in loose wet avalanches from steep solar aspects. Wet slab avalanches are possible if loose snow propagates on a buried crust.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Be alert to conditions that change with elevation.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Persistent Slabs

Continued warm and sunny weather may add enough heat to the snowpack to “wake-up” persistent weak layers buried in the snowpack. Rapid warming of the winter snowpack can result in deeply buried weak layers propagating very large avalanches.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 31st, 2016 2:00PM