Avalanche Forecast

Issued: Jan 9th, 2019 5:01PM

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

kdevine, Avalanche Canada

South Rockies.

Deep persistent weak layers at the base of the snowpack are becoming less likely to trigger, but the consequences remain high. A conservative approach to terrain selection is still recommended.

Summary

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

Freezing levels and alpine temperatures are difficult to forecast in the coming days with mild temperatures and temperature inversions dominating the weather pattern this week.WEDNESDAY NIGHT - Mainly cloudy with isolated flurries / southwest winds, 40-60 km/h / alpine low temperature near -4THURSDAY - Mainly cloudy with isolated flurries / southwest winds,30-40 km/h / alpine high temperature near -3 / Freezing level 1500 m FRIDAY - Cloudy with sunny periods / southwest winds, 10-20 km/h / alpine high temperature near +2 / freezing level 1400 m / alpine temperature inversionSATURDAY - A mix of sun and cloud / southwest winds, 10-20 km/h / alpine high temperature near +3 / freezing level 3000 m / alpine temperature inversion

Avalanche Summary

No new avalanches have been reported in the region since Saturday.On Saturday a size 2.5 explosives triggered wind slab was reported on a southeast aspect at 2000m. On Friday an explosives triggered deep persistent slab size 2.5 was reported on an east aspect at 2100m

Snowpack Summary

20-30 cm of storm snow has fallen in the region since late last week. 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 1200 m, expect to find a crust at or near the snow surface.Large variability in snow depths still exists in the region, ranging from almost no snow to nearly 200 cm in some areas. For average snowpack areas, expect to find weak and sugary faceted snow 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.

Be cautious in areas where the snowpack transitions from deep to shallow.Watch for whumpfing, hollow sounds, shooting cracks, and recent avalanches.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Wind Slabs

Steady south and southwest winds have created 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

Expected Size

1 - 2

Valid until: Jan 10th, 2019 2:00PM