Avalanche Forecast

Issued: Jan 20th, 2020 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

Triggering storm slab avalanches remains likely as another frontal system will bring new snow and cooler temperatures on Tuesday.

Summary

Confidence

High -

Weather Forecast

MONDAY NIGHT: Light snow with up to 5 cm above 1500 m, strong wind from the south, alpine temperatures drop to -3 C.

TUESDAY: Cloudy with increasing snowfall bringing 10-25 cm of new snow, increasing with elevation and proximity to the coast, strong wind from the south, alpine high temperatures around -5 C with freezing level dropping to 1200 m.

WEDNESDAY: Cloudy with isolated flurries, light wind from the south, alpine high temperatures around -5 C.

THURSDAY: Heavy snow with 30-50 cm of snow above 1800 m and heavy rain below, strong wind from the south, alpine high temperatures around -1 C.

Avalanche Summary

Numerous small (size 1) slab avalanches were triggered by riders on Sunday, while larger (size 2) wind slab avalanches were triggered naturally and with explosives. Looking forward, continuing snowfall is expected to maintain similar conditions on Tuesday, with new snow and associated avalanche hazards increasing with elevation.

Snowpack Summary

A frontal system crossing the region on Tuesday will start with rain and transition to wet snow by the afternoon. 10-25 cm of new snow will accumulated above 1000 m. A pair of weak surface hoar layers from mid and late December existed about 70 to 160 cm below the surface in advance of the storm. These layers were given a good loading test at most elevations by the storm, but still warrant caution around steep, sheltered slopes and shallow rocky areas. A layer of sugary faceted grains and hard melt-freeze crust exists near the base of the snowpack in inland parts of the region, such as the Spearhead Range. This layer also received a good loading test by the storm, but continues to warrant avoidance of shallow rocky start zones in the alpine and upper treeline.

Terrain and Travel

  • Storm snow and wind is forming touchy slabs. Use caution in lee areas in the alpine and treeline.
  • Remember that the snowpack will be significantly different at higher elevations than lower down.

Problems

Storm Slabs

An icon showing Storm Slabs

New snow will continue to add to storm slabs at higher elevations on Tuesday. Expect the depth and reactivity of slabs to greatly increase with elevation and exposure to wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 21st, 2020 4:00PM

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