Archived

Avalanche Forecast

Mar 23rd, 2016–Mar 24th, 2016

Alpine

3: Considerable

The avalanche danger rating in the alpine will be considerable

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

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

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: South Coast.

Forecast snowfall amounts for Wednesday night and Thursday are highly variable throughout the region. Pay close attention to how much snow falls in your area, and be prepared to back off to simple terrain.

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Moderate to locally heavy snowfall is forecast for Wednesday night. The Duffey Lake area may see up to 15cm of new snow while double that amount may fall in the Coquihalla area. Generally light snowfall (up to 10cm) is forecast for Thursday; however, the convective nature of the weather pattern suggests spring "power flurries" may result in localized accumulations of up to 20cm. A dry ridge should develop on Friday bringing mainly clear skies while overcast conditions are expected on Saturday. Ridgetop winds should be moderate to strong from the southwest on Wednesday night and Thursday, and then become light for Friday and Saturday. Daytime freezing levels are forecast to sit at 1000m on Thursday, 1600m on Friday and 1400m on Saturday.

Avalanche Summary

Recent avalanche observations have been extremely limited. That said, in the neighboring Sea to Sky region natural loose wet avalanches to size 1.5 were reported to have occurred on variety of aspects and elevations on Tuesday. Forecast cooling should limit ongoing loose wet avalanche activity; however, a round of natural storm slab activity is expected on Thursday in response to new snow and strong southwest winds.

Snowpack Summary

Warm temperatures and the "greenhouse effect" from cloudy skies on Tuesday have promoted significant settlement within the recent storm snow. Dry settled powder can be found on high, north facing slopes while classic spring melt-freeze conditions exist on solar aspects above 2000m and all aspects at lower elevations. Potentially deep storm slabs are expected to form on Wednesday night and Thursday morning. Below the new snow the snowpack is strong and well-settled throughout with no notable persistent weaknesses. Cornices are huge and fragile.

Avalanche Problems

Storm Slabs

Moderate to locally heavy snowfall and strong southwest winds are expected to form reactive new storm slabs on Wednesday night and Thursday morning. Watch for increased reactivity in high elevation leeward terrain.

Be cautious as you transition into wind affected terrain.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 4

Cornices

Some cornices are the size of a bus, and will continue to grow with forecast snow and wind. Give these monsters a wide berth when traveling on or below ridge crests.

Give cornices a wide berth when travelling on or below ridges.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine.

Likelihood: Possible

Expected Size: 1 - 5