Avalanche Forecast

Issued: Jan 10th, 2019 5:03PM

The alpine rating is considerable, 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.

A big rise in temperatures may mean that the deep persistent slab rears its ugly head again. Much uncertainty exists as to what this layer will do as temperatures climb. High levels of uncertainty are best managed with conservative terrain selection.

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 weekend.THURSDAY NIGHT - Mainly cloudy / southwest winds, 10-20 km/h / alpine low temperature near -5 / freezing level 1100 m / alpine temperature inversionFRIDAY - Mainly cloudy / southwest winds, 10-30 km/h / alpine high temperature near +2 / Freezing level 1500 m / alpine temperature inversionSATURDAY - A mix of sun and cloud / southwest winds, 20 km/h / alpine high temperature near +5 / freezing level 3000 m / alpine temperature inversionSUNDAY - Sunny with cloudy periods / southwest winds, 20-30 km/h / alpine high temperature near +6 / freezing level 3000 m / alpine temperature inversion

Avalanche Summary

A few size 1 natural and explosives triggered avalanches were reported in the region on Thursday.

Snowpack Summary

10-20 cm of recent storm snow has been redistributed by strong winds and has formed wind slabs at upper elevation. This new snow 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. Warming temperatures and sunshine over the coming days could re-activate this layer, resulting in a possible avalanche cycle.

Problems

Deep Persistent Slabs

Deeply buried weak layers remain a concern, especially as temperatures rise.

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

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.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Jan 11th, 2019 2:00PM