Avalanche Forecast

Issued: Mar 3rd, 2018 4:22PM

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

cgarritty, Avalanche Canada

Lizard-Flathead.

The sun packs a powerful punch at this time of year. Consider the avalanche danger to be one step higher around slopes that see direct sunshine on Sunday.

Summary

Confidence

Moderate - Timing or intensity of solar radiation is uncertain

Weather Forecast

Sunday: A mix of sun and cloud with light flurries in the evening. Light southwest winds. Alpine high temperatures of -8.Monday: Mainly cloudy with isolated flurries and a trace of new snow. Moderate southwest winds. Alpine high temperatures of -10.Tuesday: A mix of sun and cloud. Light southwest winds. Alpine high temperatures of -10.

Avalanche Summary

Storm snow has grown touchy cornices and formed widespread soft storm slabs near ridge tops and open areas at treeline and below. On Thursday and Friday, explosives control in the Fernie area produced loose dry and storm slab releases reaching from size 1.5 to 2.5 with some slabs reaching up to 80 cm in depth.On Wednesday there were reports of several natural and skier triggered size 1 loose, dry storm snow releases on all aspects above 1700 m, as well as a few size 2-2.5 natural storm slab releases on northeast aspects that where possibly cornice triggered.Tuesday a size 2.5 natural storm slab release that was likely triggered by a cornice collapse, was reported on a northerly aspect in the alpine. Cornice collapses up to size 1.5 were also reported but did not produce slab releases on the slopes below.

Snowpack Summary

50-60 cm of new low density snow accumulated in the region over Friday night. This brings snowfall totals from the past week to about 100 cm. This storm snow overlies various old surfaces including old hard wind slabs, crusts, facets and more isolated surface hoar. Also in the upper to mid snowpack, a surface hoar layer buried mid-February is now 80 to 100 cm below the surface on sheltered northerly aspects.Deeper in the snowpack, the widespread mid-December weak layer sits about 200 cm deep. This consists of a crust, facets or surface hoar.Near the base of the snowpack, a crust/facet layer could be awoken from a thin-spot trigger point, or with a very large load like a cornice fall.

Problems

Storm Slabs

All that new snow will need several days to settle and bond to the surface. As it does, natural avalanching will taper off while human triggering potential remains high. Stick to supported slopes and watch diligently for signs of slab formation.

Watch for signs of instability such as recent avalanches or shooting cracks.Pay attention to overhead hazards like cornices, which are large and fragile.Avoid exposure to sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2.5

Loose Dry

Deep accumulations of new low density snow may continue to release easily in loose dry avalanches on Sunday. This may occur naturally in steep terrain, as well as with human triggers. Watch for terrain traps where sluffs can form deep deposits.

Be aware of party members below you that may be exposed to your sluffs.Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Mar 4th, 2018 2:00PM