Avalanche Forecast

Issued: Mar 31st, 2017 4:46PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is moderate. Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.

triley, Avalanche Canada

South Rockies.

Another warm day with high freezing levels is forecast for Saturday. Watch for moist or wet snow early in the day if there is not a good re-freeze overnight.

Summary

Confidence

Moderate - Freezing levels are uncertain on Saturday

Weather Forecast

Overnight: Some cloud developing overnight that may limit crust development. Saturday: Mostly clear or scattered cloud with strong westerly winds and daytime freezing up to 2200 metres. Sunday: Mostly cloudy with 3-5 cm of convective flurries and moderate gusty west winds. Daytime freezing around 1500 metres. Monday: Re-freeze to valley bottom expected. Chance of snow developing from the northeast.

Avalanche Summary

On Friday in the Elk Valley North area, there were numerous loose wet avalanches up to size 2.0 at all elevations on solar exposed aspects. The valley fog in the morning may have reduced the effects of the sun below treeline.

Snowpack Summary

On Friday, the sun was strong at higher elevations and the surface snow became moist or wet in the Elk Valley North. Castle Mountain reported 26 cm of new snow overnight, that I suspect must have settled rapidly due to the strong sun and high freezing levels. On Thursday in Crowsnest North, the sun was strong in the morning and solar aspects became moist up into the alpine. There was still some dry snow on north aspects in the alpine. The bottom third of the snowpack is composed of weak facets and full-depth avalanches over this basal weakness remain a concern, and may be triggered by large loads like cornice falls, or strong solar radiation on a clear day.

Problems

Wind Slabs

Wind slabs may continue to be triggered in the alpine on shaded slopes.

Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Snow may become moist or wet at lower elevations. This may happen early in the day if there is not a good re-freeze overnight.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

This problem continues to be a concern until temperatures cool down and we see a good overnight freeze.

Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.Recognize and avoid avalanche runout zones.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 4

Valid until: Apr 1st, 2017 2:00PM