Avalanche Forecast

Issued: Mar 24th, 2019 4:45PM

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

cgarritty, Avalanche Canada

Purcells.

Cloudy areas should see loose wet avalanche problems diminish a bit on Monday. Expect more of the same active loose wet avalanche conditions on any slopes that see strong sun.

Summary

Confidence

Moderate -

Weather Forecast

Sunday night: Mainly cloudy. Light south winds.Monday: Mainly cloudy with isolated flurries bringing a trace of new snow. Light rain below about 1600 metres. Light south winds. Alpine high temperatures around 0 with freezing levels to 2000 metres.Tuesday: Cloudy with scattered flurries bringing a trace to 10 cm of new snow. Light rain below about 1200 metres. Precipitation easing overnight. Light to moderate southwest winds. Alpine high temperatures around -3 with freezing levels to 1600 metres.Wednesday: Mainly cloudy. 24 hour new snow totals of approximately 5-20 cm. Light east winds. Alpine high temperatures around -3 with freezing levels around 1700 metres.

Avalanche Summary

Many wet loose avalanches were observed between last Sunday and Friday. They were large (up to size 3), occurred mostly on southeast to southwest aspects, and at all elevations. Many of these avalanches scoured to basal weaknesses. A notable deep persistent slab avalanche released on Wednesday, likely triggered by a cornice fall. It was 100 cm deep on a northeast aspect at 2900 m.

Snowpack Summary

Forecast trace snowfall will accumulate above a surface of melt-freeze crust in most areas above 1500 metres, with the exception of north aspects above 2000 metres, where it will land on settled and preserved dry snow. Below about 1500 metres, light precipitation as rain will land on variably isothermal (slushy) and crusty surfaces. Any added moisture will promote isothermal conditions where they don't already exist. The mid snowpack is generally consolidated and strong, but exceptions may exist on north aspects above 2000 m, where a gradually strengthening layer of faceted grains buried 40 to 60 cm deep may still be preserved below an overlying slab of old and hard wind-affected snow.The base of the snowpack is composed of weak faceted snow which may coexist with a melt-freeze crust. One very large persistent slab was observed to have failed at this layer during the recent warming event.

Problems

Loose Wet

If the snow feels slushy, there is potential for triggering a loose wet avalanche. Expect heightened danger on steep slopes that see strong sun or rain. Large loose wet avalanches may start small and move slowly, but they can be highly destructive.

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.Reduce your exposure to areas with overhead hazard during periods of rain or strong sun.

Aspects: South East, South, South West.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2.5

Persistent Slabs

A few weak layers still exist within the snowpack. The recent hot weather may have influenced these layers, but time is needed to assess how much they have changed.

Best to avoid thin, rocky terrain, where it may be easier to trigger deeper weak layers.Back off if you encounter whumpfing, hollow sounds, or shooting cracks.Avalanche hazard may have improved, but be mindful that buried instabilities are still present.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Mar 25th, 2019 2:00PM