Avalanche Forecast

Issued: Mar 25th, 2016 8:47AM

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

triley, Avalanche Canada

Cariboos.

There is some uncertainty if we will have sun all day, or if there may be a band of high cloud for most of the morning. Strong solar radiation may result in loose wet avalanches and natural cornice falls.

Summary

Confidence

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

Weather Forecast

Mostly clear overnight with light westerly winds and freezing down to valley bottoms. On Saturday, mostly clear with light southwest winds and freezing levels rising to 1700 metres. Cloud and light precipitation developing by Sunday morning with freezing down to at least 1000 metres. On Sunday, cloudy with 3-5 cm of snow and freezing levels rising up to 1300 metres. Light snow and moderate northwest winds on Monday, before the next ridge of high pressure brings back the clear skies.

Avalanche Summary

On Thursday, we had reports of storm slab avalanches up to size 2.5 in isolated steep unskiable terrain. I suspect that storm slabs continued to be easy to trigger on Friday on shaded aspects, and loose moist or wet avalanches released naturally during periods of strong solar radiation.

Snowpack Summary

The dry new storm snow on Thursday settled with warm temperatures and periods of strong solar radiation. Moist snow was reported on solar aspects in the alpine, and up to at least 1800 metres on shaded aspects. There are several thin crusts in the upper snowpack on all but shaded north aspects. Expect a new surface crust to develop overnight with forecast freezing level dropping down to valley bottoms. 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 during periods of strong solar radiation and/or daytime warming.

Problems

Cornices

Natural cornice falls are likely during periods of strong solar radiation and warm daytime temperatures. Cornice falls may trigger deeply buried persistent weak layers.

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Storm Slabs

Storm slabs may continue to be easy to trigger on shaded aspects. Storm snow may release as loose wet avalanches on solar aspects during periods of clear and sunny weather.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Avoid freshly wind loaded features.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

The persistent weak layer of buried surface hoar, facets, and crusts is buried down close to a metre. This has become a low probability of triggering, but high consequence of large avalanche problem. Choose well supported terrain without convexities.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Use conservative route selection, stick to moderate angled terrain with low consequence.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

3 - 6

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