Archived

Avalanche Forecast

Mar 15th, 2017–Mar 16th, 2017

Alpine

4: High

The avalanche danger rating in the alpine will be high

Treeline

3: Considerable

The avalanche danger rating at treeline will be considerable

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: Northwest Coastal.

Freezing levels are expected to drop down to near valley bottoms overnight. Some very low elevation terrain may continue to release as loose wet avalanches.

Confidence

Moderate - Freezing levels are uncertain on Thursday

Weather Forecast

Overnight: Freezing level dropping down to near valley bottoms, 5-8 cm of new snow, moderate southwest winds. Thursday: Daytime freezing level up to about 500 metres, 10-20 cm of new snow, moderate southwest winds. Friday: Daytime freezing level around 400 metres, 5-8 cm of new snow, light-moderate southwest winds. Saturday: Daytime freezing level around 400 metres, flurries or periods of light snow, moderate southwest winds.

Avalanche Summary

Widespread natural avalanche cycle reported on Tuesday. Natural wet slab avalanches up to size 2.5 and loose wet avalanches up to size 1.5. Reports have been limited due to poor visibility and travel conditions.

Snowpack Summary

Storm slabs continue to develop above 1100 metres. These storm slabs are deep 30-60 cm, with much deeper areas where the wind has transported the snow. Below 1100 metres the snow is moist or wet. The overall results will be widespread touchy storm slabs at higher elevations and unstable wet snow at lower elevations. The storm snow is also stressing a weak interface from February composed of facets, crust, and surface hoar buried over a metre deep. Given the recent activity on this layer before the storm, it should be very reactive during this storm.

Avalanche Problems

Storm Slabs

Storm slabs are expected to continue to develop with each pulse of new snow and wind.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely - Very Likely

Expected Size: 2 - 3

Persistent Slabs

The natural storm slab cycle is expected to release persistent slab avalanches. Cornice falls may trigger deeply buried persistent weak layers.

Avoid all avalanche terrain.Be aware of the potential for full depth avalanches due to deeply buried weak layers.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 2 - 4

Wet Slabs

Heavy rain on snow may trigger wet slab or loose wet avalanches at lower elevations. This problem may be short lived due to the forecast cooling trend.

If triggered the loose wet sluffs may step down to deeper layers resulting in large avalanches.Use extra caution on slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 3