Avalanche Forecast

Issued: Jan 7th, 2019 4:38PM

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

mbender, Avalanche Canada

South Rockies.

Weak layers buried near the bottom of the snowpack remain a concern. A conservative approach to route selection is recommended.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

MONDAY NIGHT: Clear periods, light to moderate west winds, alpine temperature -10 CTUESDAY: Cloudy with sunny periods, Light southwest winds, alpine temperature -6 CWEDNESDAY: Mainly cloudy with isolated flurries, light southwest winds, alpine temperature -2 C, possible temperature inversionTHURSDAY: Mainly cloudy with isolated flurries, light to moderate southwest winds, alpine temperature -4 C, freezing level 1500m

Avalanche Summary

Most recent avalanche activity has been reported as an explosives controlled deep persistent slab size 2.5 release on an east aspect at 2100m on Friday and also on Saturday of a size 2.5 explosives controlled wind slab release on a southeast aspect at 2000m.

Snowpack Summary

Large variability in snow depths still exists in the region, ranging from practically no snow to almost 200 cm. Upwards of 50-60 cm of snow fell late last week above 1500 m. The snow fell with strong southwest winds and sits on previous hard wind slabs, a scoured and shallow snowpack on exposed ridges, and soft snow in sheltered areas. Below 1500 m, expect to find a hard crust at or near the snow surface.For average snowpack areas, expect to find weak and sugary faceted grains around 50 to 100 cm deep, which extend to the ground. This weak bottom half of the snowpack has been the culprit for large avalanches in the region over the past few weeks.

Problems

Deep Persistent Slabs

Deeply buried weak layers remain a concern even as the storm snow from last week has settled and bonded. Avalanches triggered on this layer will likely scour to the ground, resulting in large avalanches.

Choose low-angled, mellow terrain without any consequences.Avoid steep convexities or areas with a thin or variable snowpack.Watch for whumpfing, hollow sounds, shooting cracks, and recent avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

Steady south and southwest winds have created reactive wind slabs in the lee of terrain features.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Jan 8th, 2019 2:00PM