Avalanche Forecast

Issued: Mar 20th, 2019 3:19PM

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

Avalanche Canada mconlan, Avalanche Canada

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The hot and sunny weather persists on Thursday, which will likely continue the natural avalanche cycle. The danger will be the highest when the day heats up, so make sure you are completely out of avalanche terrain, with no overhead exposure.

Summary

Confidence

High -

Weather Forecast

WEDNESDAY NIGHT: Clear skies, light southeast wind, alpine temperature 6 C, freezing level 3400 m.THURSDAY: Clear skies, light southeast wind, alpine temperature 5 C, freezing level 3200 m.FRIDAY: Clear skies, light south wind, alpine temperature 4 C, freezing level 2900 m.SATURDAY: Cloudy with rain and snow, accumulation 5 cm of snow above 2000 m or 5 mm of rain below 2000 m, light southwest wind, alpine temperature -1 C, freezing level 2000 m.

Avalanche Summary

Many wet loose avalanches were observed on Wednesday, from small to large (size 1 to 3). They occurred on southeast to southwest aspects and at all elevations. Wet slab avalanches were also observed, likely releasing on the weak layer described in the snowpack summary.This avalanche cycle is expected to continue, as temperatures remain exceptionally warm and the sun shines strong.

Snowpack Summary

The warm air and sunny skies have produced moist snow to ridge top on all aspects. The upper 20 to 30 cm of snow may slide easily during the day, either as loose wet snow or as a cohesive slab, as it sits over weak faceted grains or a melt-freeze crust on sun-exposed slopes. The moist snow may freeze into a melt-freeze crust overnight.A weak layer of faceted grains and/or feathery surface hoar crystals buried in mid-January may be found around 50 to 90 cm deep. Although this layer has been dormant for a few weeks, the current warm conditions may awaken this layer. Steep cutblocks and large open glades at lower elevations are the most likely places to trigger this layer.The base of the snowpack is composed of weak faceted snow, which may be associated with a melt-freeze crust. The warm air and sunny skies could increase the likelihood of triggering very large avalanches on this layer.

Problems

Loose Wet

An icon showing Loose Wet
The upper snowpack is destabilizing in the day with hot and sunny weather, producing large avalanches. The most problematic time is with maximum warming during afternoon hours. Best to avoid avalanche terrain on or beneath southerly aspects.
Constantly look up: stay well-away from overhead exposure, as avalanches could run full-path.Avoid avalanche terrain during the afternoon heat, particularly on sun-exposed slopes.Cornices are large and looming and could trigger avalanches on slopes below them.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs
A slab of snow is poorly bonded to weak, sugary faceted snow or a melt-freeze crust. The warm temperature and strong sun have increased the likelihood of triggering a slab avalanche by humans, cornices, and naturally.
Avoid corniced ridges; they are weak and could trigger persistent slab avalanches.Avalanches could reach valley bottom; avoid all overhead exposure.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Valid until: Mar 21st, 2019 2:00PM