Avalanche Forecast

Issued: Apr 2nd, 2017 3:00PM

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

shorton, Avalanche Canada

Northwest Inland.

Watch for changing snow conditions when the sun comes out. Slab avalanche activity is possible at higher elevations, and will be more likely when the snow is soft and warm.

Summary

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

MONDAY: Sunny skies, light winds, and freezing level rising to 1200 m after an overnight freeze.TUESDAY: Overcast with light snow in the evening, increasing south wind, and freezing level climbing to 1400 m. WEDNESDAY: Scattered flurries with about 5 cm, strong south wind, and freezing level around 1400 m.

Avalanche Summary

A natural cornice fall released a wind slab or perhaps a persistent slab on a northeast aspect that was size 2.5; this was reported from the Microwave on Thursday but may have occurred on Wednesday (see the full MIN report here). Storm slabs up to size 2.5 were reported from the western extent of the region in the Howson's, where the snowpack is more like the Northwest Coastal region. No new avalanches have been reported from the rest of the region.

Snowpack Summary

Light snow combined with moderate southwest winds has developed wind slabs in the alpine and in some exposed treeline locations. Periods of sun and high daytime freezing levels have developed crusts below treeline and on sun exposed terrain at all elevations. The snow may be moist or wet below treeline during the warmest part of the day. The February crust and facet layer was reported to be down 75-90 cm in the Houston Telkwas sled area on Wednesday. The deep persistent weak layer of facets and/or a crust that were buried early in the winter are still lingering near the bottom of the snowpack. This MIN report found the deep weak layer strengthening in the Telkwas.

Problems

Wind Slabs

Wind slabs are likely lingering in the lee of exposed terrain. Fresh cornices may also be weak and fall off naturally when hit by the sun.

Use caution in lee areas. Recent wind loading have created wind slabs.Be careful with wind loaded pockets. Be aware of wide variation in snowpack depth

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

A weak layer of facets and/or a crust that developed early in the winter lies near the bottom of the snowpack. Strong solar radiation or a cornice fall are possible triggers.

Avoid steep convexities or areas with a thin or variable snowpack.Cornices become weak with daytime heating, so travel early on exposed slopes.Minimize exposure to sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Apr 3rd, 2017 2:00PM