Avalanche Forecast

Issued: Apr 4th, 2015 8:36AM

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

pgoddard, Avalanche Canada

Cariboos.

Avoid exposing yourself to slopes that are getting affected by the springtime sun. The danger rating reflects conditions during the warm part of the day.

Summary

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Sunday

Weather Forecast

Light snow fall is expected on Sunday, petering to flurries on Monday. On Tuesday, a ridge moves in, starting a few days of fine, sunny weather. The freezing level is around 1500 m by day, falling towards valley floor by night. Winds are generally light.

Avalanche Summary

A handful of recent large avalanches have been reported over the last few days. Many of these have been on north aspects, with the odd event on other aspects. There has also been a number of cornice falls.

Snowpack Summary

Recent squally snow showers have brought 10-25 cm of snow, which has been shifted into wind slabs. This new snow sits above a crust which varies in thickness with elevation. Cornices are large and should be given a respectful berth. Sun is likely to destabilize new snow and cornices.Two crust/facet interfaces, formed in March and February, sit about 80-120 cm deep in the snowpack. These weaknesses are becoming more stubborn to trigger, but still react in snowpack tests and have potential for wide propagations and very large avalanches if triggered. Most likely trigger spots would be thin snowpack areas, or triggering with a large load like a cornice fall.Basal facets are on operators' list of concerns. Deep snowpack issues sometimes wake up in the spring, so should not be forgotten.

Problems

Loose Wet

Sun on new snow is likely to spark a cycle of loose wet avalanches, especially on steep solar aspects.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Time your travel to avoid being on or underneath slopes that are getting cooked.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Cornices

Cornices are large and may be fragile. They may also trigger wind slabs on slopes below.

Give cornices a wide berth when travelling on or below ridges.>Use caution in lee areas in the alpine. Recent wind loading has created wind slabs.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

Buried persistent weak layers may still be reactive to human-triggering and large avalanches remain possible. Smaller avalanches in motion or a cornice failure could step down to one of these deeper layers.

Choose conservative lines.>Caution around convexities or areas with a thin or variable snowpack.>Dig down to find and test weak layers before committing to a big line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Apr 5th, 2015 2:00PM