Avalanche Forecast

Issued: Apr 3rd, 2018 4:41PM

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

mgrist, Avalanche Canada

South Coast Inland.

Fresh snow may hide wind slabs on north aspects. Be wary of cornices: they are large and fragile, especially in the north of the region.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Thursday

Weather Forecast

Only small amounts of snow on Wednesday with heavier snow fall (or rain) on Thursday-Friday. Freezing levels will slowly increase.WEDNESDAY: Occasional flurries (up to 5 cm, with more possible in the south) / Moderate south west wind / Alpine temperature -5 / Freezing level 500m rising to 1400m in the afternoon THURSDAY: (Wet) flurries (5-10 cm) or rain at lower elevations / Light to moderate south-west wind / Alpine temperature -3 / Freezing level 1400mFRIDAY: Wet flurries (5-10 cm possible) or rain at lower elevations / Moderate south west wind / Alpine temperature -2 / Freezing level 1800m.

Avalanche Summary

On Saturday two skiers triggered a size 1 wind slab (40cm thick crown) in a down wind (lee) area, north facing aspect near 2060m elevation up Phelix creek. See the MIN post for more details. On Thursday, skiers triggered a size 2 wind slab that caught and carried a skier near Steep Creek in the Duffey zone. Slab thickness was 15-20cm. See this MIN post for more details. A week ago there was report of a skier triggered wind slab from the north of the region in the alpine near ridge top running on a layer of facets buried March 21. See this MIN post for more details.

Snowpack Summary

Only small amounts of new snow (2-4cm) in the north and modest amounts (5-14cm) of low density snow in the south on Tuesday. Winds were gusting moderate from the (north) east in the Coquihalla. This adds to the new snow from Sunday, which resulted in some local accumulations of up to 25cm.This new snow sits on melt-freeze crusts on sunny aspects at treeline and below or it sits on hard wind slabs in the alpine, and possibly some soft wind slabs on shady aspects.Snow from a week ago sits on a deeper crust that is present at all elevations on sunny aspects as well as low elevation northerly aspects. On northerly and east aspects between 1900m and 2250m the old storm snow sits on a mix of rounding surface hoar and/or facets buried March 21st, and found down anywhere from 20-70cm. The distribution the March 21st layer is patchy, and has resulted in some hard to trigger avalanches ranging from size 1 to 2.5.

Problems

Wind Slabs

Moderate to strong south-easterly winds have built wind slabs. These slabs seem to be most reactive in the north of the region, specifically on shady aspects where they may be sitting on a layer of weak facets or surface hoar.

Watch for whumpfing, hollow sounds, and shooting cracks.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, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Cornices

Cornices are large and fragile in the north of the region: Give them a wide berth and a lot of respect.

Give cornices a wide berth when traveling on or below ridges.Pay attention to overhead hazards like cornices which could trigger persistent slabs.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 4th, 2018 2:00PM