Avalanche Forecast

Issued: Apr 20th, 2019 4:37PM

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

Parks Canada conrad janzen, Parks Canada

A very widespread cycle of natural and skier triggered avalanches up to size 3 was observed Saturday. Steep slopes will remain primed for human triggering on Sunday. Make conservative terrain choices until the storm snow has a chance to bond.

Summary

Weather Forecast

Cool temperatures with freezing levels at valley bottom are expected Saturday night. Generally clear skies (lots of solar heating!) and light W winds are expected on Sunday. Monday looks similar with a bit more wind and slightly warmer temperatures.

Snowpack Summary

60-100 cm of snow in the last week with snowpack depths reaching seasonal highs above 2000 m. Strong to extreme W winds with 20-40+ cm of snow on Friday created widespread storm slabs in alpine areas and sluffing in steep terrain. This recent snow sits on a variety of surfaces above treeline. Moist snow at lower elevations and on solar aspects.

Avalanche Summary

On Saturday Visitor Safety staff observed widespread natural and skier triggered slab avalanches up to size 3 above 2000 m with 50-200 cm thick crowns, especially on North and East aspects. Wet loose avalanches were observed to size 2 at lower elevations and steep south aspects, with sluffing on steep N aspects and several new cornice failures.

Confidence

Problems

Storm Slabs

An icon showing Storm Slabs

Significant snowfall over the last week combined with two periods of strong to extreme wind has created widespread storm slabs in the alpine. These are primed for human triggering. Minimize exposure to large slopes and cornices in the alpine.

  • Use conservative route selection, stick to supported terrain features, avoid overhead hazards.
  • New snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Loose Wet

An icon showing Loose Wet

Lower elevations and South aspects will have a crust from Saturday, but intense solar inputs will weaken these crusts on Sunday allowing for wet loose avalanches later in the day. Travel and return early before things heat up.

  • Use extra caution on slopes if the snow is moist or wet.
  • If triggered, loose wet sluffs may step down to deeper layers resulting in larger avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Apr 21st, 2019 4:00PM