Avalanche Forecast

Issued: Mar 29th, 2018 4:26PM

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

mconlan, Avalanche Canada

Lizard-Flathead.

Precipitation should fall with strong winds and with a freezing level around treeline. Expect wind slabs in exposed terrain features and wet snow at low elevations. Watch your overhead exposure, as cornice falls could trigger slabs on slopes below.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

FRIDAY:Â Cloudy with light snowfall, accumulation 5 to 15 cm, moderate to strong westerly winds, alpine temperature -5 C, freezing level 1500 m.SATURDAY: Sunny with a few clouds, light easterly winds, alpine temperature -10 C, freezing level 1000 m.SUNDAY: Increasing clouds with light snowfall, moderate southwesterly winds, alpine temperature -5 C, freezing level 1600 m.

Avalanche Summary

On Wednesday, large (size 2 to 3) wind slabs were observed in the region, being triggered naturally and by explosive control.Â They were generally on easterly aspects, 20 to 30 cm deep, and at treeline and alpine elevations.Cornices have also been reactive this week, with numerous releases from natural and explosive triggers.Â

Snowpack Summary

Wind slabs exist on all aspects, produced from redistribution of last weekendâ€™s storm snow from variable wind directions. This snow sits on a melt-freeze crust on sunny aspects and all aspects below 1600 m, as well as surface hoar on north aspects above 1600 m.Â At ridgetop, cornices are large and have been failing in the past days.Â At lower elevations, expect to find moist snow on the surface with daytime warming and potential rainfall, which will freeze into a crust with cooler overnight temperatures.Deeper in the snowpack, the mid-December and late-November weak layers are composed of crusts and sugary facets, which are down 150 to 300 cm. These layers are currently considered dormant but may be awoken by a large trigger, such as a cornice fall.

Problems

Wind Slabs

Winds from variable directions have produced wind slabs in exposed terrain features. Be particularly cautious when travelling below corniced ridges, as a cornice could trigger wind slabs on slopes below.

Use extra caution on slopes if snow becomes moist or wet with sun exposure.Use ridges or ribs to avoid pockets of wind loaded snow.Watch for reverse wind loading. Intense snow transport from northeast winds was observed Wednesday.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Precipitation may fall as rain at low elevations. Be cautious if you feel moist snow on the surface, as loose wet avalanches could be reactive.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.Use extra caution on slopes if the snow is moist or wet.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 30th, 2018 2:00PM