Avalanche Forecast

Issued: Mar 24th, 2019 4:45PM

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

cgarritty, Avalanche Canada

North Columbia.

Avalanche problems that peaked during the warm spell should diminish on Monday, but not disappear.

Summary

Confidence

Moderate -

Weather Forecast

Sunday night: Mainly cloudy with isolated flurries bringing a trace to 5 cm of new snow. Light southeast winds.Monday: Cloudy with scattered flurries bringing 2-6 cm of new snow, light rain below about 1500 metres. Light to moderate south winds. Alpine high temperatures around 0 with freezing levels to 1900 metres.Tuesday: Cloudy with flurries bringing 5-10 cm of new snow with light rain below about 1100 metres, continuing overnight. Light to moderate southwest winds. Alpine high temperatures around -2 with freezing levels to 1500 metres.Wednesday: A mix of sun and cloud with cloud decreasing over the day and 24 hour new snow totals of 10-30 cm. Light northeast winds. Alpine high temperatures around -1 with freezing levels around 1700 metres.

Avalanche Summary

The wet loose avalanche cycle from last Sunday to Friday diminished as cooler, seasonal temperatures returned to the mountains on Saturday. Evidence of the cycle is widespread at all elevations, with recent avalanches up to size 3 found mostly on southeast to southwest aspects. A few large slab avalanches were also triggered on other aspects, with many of them running to valley bottom.Looking forward, avalanche problems will be split between lingering loose wet problems (areas of isothermal snow that haven't already avalanched) and isolated persistent slab problems on high north aspects. The latter may present as a large old wind slab that remains triggerable because it sits on an interface of preserved cold, faceted (sugary) snow. Small new wind slabs are expected to form gradually as new snow accumulates at higher elevations.

Snowpack Summary

Forecast light new snow amounts 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 bury settled and preserved dry snow. Below about 1500 metres, precipitation as rain will land on variably isothermal (slushy) and crusty surfaces. This moisture will promote isothermal conditions where they don't already exist. The remainder of the snowpack is generally consolidated and strong. Exceptions may exist on northerly 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.

Problems

Persistent Slabs

On isolated north aspects above 2000 metres, a 40 to 60 cm thick slab of snow may be poorly bonded to weak, faceted (sugary) snow. This layer is likely most problematic where the overlying slab is composed of hard, wind-affected snow.

Increase caution around previously wind-loaded features near ridge crests and in steep terrain.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: North, North East, North West.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Loose Wet

Light rain will help to maintain loose wet avalanche problems on steep slopes that haven't already avalanched. If the snow feels slushy, there is potential for loose wet avalanches.

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.Avoid exposure to areas with overhead hazard during periods of rain.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

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