Avalanche Forecast

Issued: Mar 27th, 2016 9:00AM

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

bcorrigan, Avalanche Canada

Northwest Inland.

Rapid warming make push the hazard higher than forecast. Conservative terrain choices are the best bet these days.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

The snowfall from this weekend will taper off with a few scattered flurries on Monday morning, but nothing significant as far as precipitation goes. A high pressure ridge is forecast to be the big news in the weather pattern for next week. MONDAY: Freezing level dropping to 700 m overnight, then beginning to rise to 1500 m by midday. No precipitation in the forecast, winds forecast to be light to moderate from the northwest. TUESDAY: Freezing level starts at 2200m early Tuesday morning, then begins to rise reaching 3000 m by early Tuesday evening. Light to moderate winds mostly from the north west, no precipitation in the forecast. WEDNESDAY: Clearing skies and freezing level climbing to 3300m. Winds from the north west, no precipitation forecast.

Avalanche Summary

Few reports of avalanches from yesterday but are more likely the result of poor visibility rather than lack of activity. Cornices, soft storm slabs and wind slabs at higher elevations, loose-wet avalanches as the spring sun comes,... out are the prime concerns these days.

Snowpack Summary

At treeline and above small wind slabs overly a variety of surfaces include crust on solar aspects above 1300 m, moist or refrozen snow on all aspects below 1300 m, and settled wind slabs in exposed high elevation terrain. Surface hoar from March 23rd is still being mentioned in the northern half of the region, and now may be covered by up to 20cm of recent storm snow. Professional operators are tracking two deep weak layers from early-January and February that are now down about 1 meter or more. These layers are generally dormant but might wake up with increased warming or a heavy trigger (like a cornice fall). Basal facets exist in some areas and have been shown to be reactive in the north of the region. Rapid warming may wake up deeply buried weak layers.

Problems

Wind Slabs

Wind slabs may become reactive as the temperature rises.

Use ridges or ribs to avoid pockets of wind loaded snow.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices are large and will become weak with rising temperatures.

Extra caution needed around cornices with current conditions.>Pay attention to overhead hazards like cornices.>Cornices become weak with daytime heating. >

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Deep Persistent Slabs

Rising temperatures make make these layers reactive. The snowpack does not tolerate rapid change very well.

Be aware of the potential for full depth avalanches due to deeply buried weak layers. >Be aware of thin areas that may propagate to deeper instabilities. >Avoid exposure to sun exposed slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 28th, 2016 2:00PM