Avalanche Forecast

Issued: Apr 2nd, 2018 4:57PM

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. Watch for rapid snow loading in the south (Coquihalla) on Tuesday, and be prepared to dial back terrain use.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Tuesday

Weather Forecast

Unsettled weather until the next system arrives on Wednesday. Freezing levels will increase slowly & steadily.TUESDAY: Cloudy with flurries Monday overnight and into the morning (5-15 cm, with higher totals possible in the South) / Light to moderate south west wind (some strong west winds in the Coquihalla and Manning) / Alpine temperature -7 / Freezing level 1200m WEDNESDAY: Cloudy with flurries (5-10 cm) / Moderate south west wind / Alpine temperature -6 / Freezing level 1300m THURSDAY: Snow (5-15cm) / Light to moderate southwest wind / Alpine temperature -3 / Freezing level 1600m

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

Convective flurries and gusty winds on Easter Sunday resulted in some local accumulations up to 25cm; however, most areas saw 10-15cm of new snow. 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.Winds picked up earlier on Sunday morning, creating fresh wind slabs on northerly 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 large 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 southerly 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.

Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.Watch for whumpfing, hollow sounds, and shooting cracks.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Cornices

Cornices are large and fragile: Give them a wide berth and a lot of respect.

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

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Apr 3rd, 2018 2:00PM