Avalanche Forecast

Issued: Jan 10th, 2019 5:02PM

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

kdevine, Avalanche Canada

Lizard-Flathead.

Storm snow from the past few days has formed slabs at treeline and in the alpine. These may become more reactive to human triggering as temperatures rise, especially if the sun comes out.

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 with isolated flurries / southwest winds, 10-25 km/h / alpine low temperature near -4 / freezing level 1100 m / alpine temperature inversionFRIDAY - Mainly cloudy with isolated flurries / southwest winds, 10-30 km/h / alpine high temperature near 0 / Freezing level 1500 m / alpine temperature inversionSATURDAY - A mix of sun and cloud / southwest winds, 20 km/h / alpine high temperature near +2 / freezing level 3000 m / alpine temperature inversionSUNDAY - Sunny with cloudy periods / southwest winds, 20-30 km/h / alpine high temperature near +3 / freezing level 3000 m / alpine temperature inversion

Avalanche Summary

Several explosives triggered avalanches to size 2 were reported on southeast and northeast aspects between 1850 m and 2100 m on Thursday.A size 1.5 natural storm slab avalanche was reportedÂ on Wednesday.

Snowpack Summary

15-30 cm of recent new snow combined with mild temperatures and strong winds has formed storm slabs at alpine and treeline elevations. The new snow sits on previous storm snow and wind slabs above 1500 m, and a melt freeze crust below 1500 m.In sheltered areas around treeline, 70-120cm of recent snow may sit on a weak layer of surface hoar (feathery crystals). In the east of the region near Corbin, a persistent weak layer that formed in early December may still be found 90 to 150 cm deep. This layer mostly consists of faceted (sugary) snow with some isolated areas also containing surface hoar. While professionals are still tracking this layer, it has not been reactive for some time now. However, the warming event that is forecast in the coming days may wake this layer up.There is a mix of crusts and facets that formed in late October/early November near the bottom of the snowpack. This layer may only be an issue on steep slopes where the snowpack is shallow.

Problems

Storm Slabs

Up to 30 cm of recent new snow combined with strong southwest winds and mild temperatures has formed storm slabs which will likely be most reactive in wind loaded areas.

Extra caution needed around cornices with current conditions.Be cautious as you transition into wind affected terrain.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

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