Avalanche Forecast

Issued: Apr 1st, 2018 4:12PM

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

mgrist, Avalanche Canada

South Coast Inland.

In the north of the region, wind slabs may sit on a weak layer of facets or surface hoar on shady aspects in the alpine and tree line. See Friday's Forecaster Blog for more details: goo.gl/8Z83CvAvoid sunny slopes if the sun comes out in full force.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain on Monday

Weather Forecast

Monday will see mixed weather before a more organized system arrives on Wednesday. Convective activity could result in locally higher accumulations. Temperatures are staying cool for this time of year. MONDAY: Mix of sun and cloud and occasional flurries in the afternoon / Light to moderate north west wind / Alpine temperature -9 / Freezing level 1000m TUESDAY: Cloudy with flurries (2-5 cm possible) / Light to moderate south west wind / Alpine temperature -7 / Freezing level 1200m WEDNESDAY: Snow (5-15cm) / Moderate south west wind / Alpine temperature -4 / Freezing level 1400m

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. On Tuesday 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

The past four days have seen only 5-15 cm of new snow in most areas (although convective activity on Sunday could produce additional local amounts of 10-15cm). Daytime warming created moist, heavy surface snow on sunny aspects, which refroze to form a crust overnight. Winds picked up on Sunday morning, creating fresh wind slabs on northerly aspects. The newer snow sits on a wide variety of surfaces: hard wind slabs, soft wind slabs on shady aspects, and the melt-freeze crusts on sunny 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 at treeline and alpine elevations the storm snow sits on a mix of large surface hoar and or facets.In the south of the region, around the Coquihalla and in Manning Park, the last storm snow overlies a recent crust that caps a well settled snowpack.

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.

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.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Loose Wet

The sun really packs a punch this time of year - if you see it come out in full force, be prepared to adjust your terrain use accordingly. Sunny periods are more likely in the north of the region on Monday.

Avoid exposure to sunny slopes.Watch for signs the snow warming up, like sluffing off cliffs and pinwheeling.Give cornices a wide berth when travelling on or below ridges.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Apr 2nd, 2018 2:00PM