Avalanche Forecast

Issued: Mar 26th, 2016 8:58AM

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.

The hazard may go higher than expected if precipitation and winds are higher forecast. Use great caution around cornice features.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

The Northwest Inland will see light precipitation through the weekend, with clearing skies late Sunday in advance of a ridge of high pressure that will dominate the weather pattern for most of next week. TODAY: Freezing level to around 1200 m, trace of snow, light to moderate southeast winds. SUNDAY: Freezing level dropping to 700 m overnight, then rising to 1300 m during the day. Possible 5 cm of snow, light winds from the southwest. MONDAY: Freezing level dropping to 700 m overnight, then beginning to rise to 1500 m by midday. No precipitation in the forecast. TUESDAY: Freezing level starts at 700 m early Tuesday morning, then begins to rise reaching 2700 m by early Tuesday evening. Light to moderate winds mostly from the west, no precipitation in the forecast.

Avalanche Summary

Loose wet avalanches on solar aspects below treeline are in the news from yesterday. It is spring, after all ! Some sluffing in steep terrain and of course, cornice failures are on everybody's minds. Natural cornice failures have been recently reported triggering avalanches up to size 2.

Snowpack Summary

At treeline and above small wind slabs overlie 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. There is a surface hoar layer formed in early March that may still be found down 50 to 70 cm. It is still being mentioned by operators in the northern half of the region. Professional operators are still tracking two deep weak layers from early-January and early-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 most areas and have been shown to be reactive in the north of the region.

Problems

Wind Slabs

Incoming storm with snow and wind will most produce wind slabs at tree line and above,

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

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Cornices

Cornices are large and ripe ! Warming temperatures will also make them weak, use great caution under their run-outs and around them on ridge tops.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Deep Persistent Slabs

No recent activity, but rapidly rising temperatures may make these deeply buried layers more reactive.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 27th, 2016 2:00PM