Avalanche Forecast

Issued: Apr 8th, 2018 4:21PM

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

jmcbride, Avalanche Canada

Northwest Inland.

Rising freezing levels and the sun's influence are the main concerns for the next few days. Watch for moist or wet snow especially on sunny aspects. Recent wind slabs may also become more sensitive to triggering with the warming trend.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TONIGHT: Mostly cloudy, light flurries. Accumulation trace. Ridge wind moderate, west. Alpine temperature near 0. Freezing level 1500 m.MONDAY: Mostly cloudy, light flurries. Accumulation trace. Ridge wind moderate, southwest. Alpine temperature near 0. Freezing level 1500 m.TUESDAY: Cloudy, flurries. Accumulation 5-10 cm. Ridge wind strong to extreme southeast. Alpine temperature near 0. Freezing level 1500 m.WEDNESDAY: Mix of sun and cloud. Ridge wind moderate to strong, southeast. Alpine temperature near 0. Freezing level 1500 m.

Avalanche Summary

There have no reports of avalanche activity since Thursday when a widespread natural avalanche cycle (up to size 2), triggered by intense wind loading was reported from the northern part of region.A natural, solar triggered size 2 avalanche was reported on Wednesday morning in the Howson range, as well as skier triggered size 1 storm slab releases on a buried sun crust (30 cm deep) on a southeast aspect at 1700 m.

Snowpack Summary

From 20 cm up to 50 cm of recent storm snow has been redistributed by strong winds and sits above a variety of crusts on all but high north aspects. Warming followed by cooling has created a surface crust on all aspects up to treeline elevations that will likely break down becoming moist or wet by the afternoon.Weak layers buried around March 19th are roughly 40 cm below the surface (up to 100 cm in deeper snowpack areas). These weak layers include surface hoar on shaded aspects at high elevations and hard crust layers on solar aspects and below treeline.Near the bottom of the snowpack, weak and sugary facets are found in shallow, rocky snowpack areas. Storm slabs have stepped down to these facets and producing very large avalanches in northern parts of the region.

Problems

Loose Wet

Recent storm snow may become unstable due to rising freezing levels and solar radiation. Watch for moist or wet snow releases especially on sunny slopes and at treeline and below.

Be increasingly cautious on sun exposed slopes.Use extra caution on slopes if the snow is moist or wet.Use caution above cliffs and terrain traps where small avalanches may have severe consequences.

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

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Wind Slabs

Strong to extreme winds have created widespread wind slabs in leeward areas at treeline and above. With warming temperatures these slabs may still be sensitive to light triggers, such as a small slough or a skier/rider.

If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.Be careful with wind loaded areas, especially near ridge crests and roll-overs.Pay attention to overhead hazards like cornices which may become fragile with daytime warming.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2.5

Valid until: Apr 9th, 2018 2:00PM