Avalanche Forecast

Issued: Apr 18th, 2022 4:00PM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Cornices and Wind Slabs.

Avalanche Canada cgarritty, Avalanche Canada

Continuous light flurries might bring just enough new snow to create a small wind slab problem to manage. Monitor new snow amounts and reactivity as you travel on Tuesday.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain.

Weather Forecast

MONDAY NIGHT: Cloudy with flurries bringing a trace to 5 cm of new snow. Moderate east winds, easing into the morning.

TUESDAY: Mainly cloudy with continuing isolated flurries and a further trace of new snow. Light east or southeast winds. Treeline high temperatures around -6.

WEDNESDAY: Cloud diminishing over the day with another trace to 5 cm of new snow from the overnight period. Light east or southeast winds. Treeline high temperatures around -4.

THURSDAY: Cloud increasing again with isolated flurries and a trace of new snow. Light southeast winds. Treeline high temperatures around -3.

Avalanche Summary

One recent cornice fall that did manage to trigger a slab was reported from a flight over the Telkwa range on Friday. On Saturday a few small loose dry avalanches were observed in steep, solar, rocky terrain. Otherwise, no new avalanches have been reported in the past few days.

On Thursday, explosives triggered wind slabs up to size 2 on south-south east aspects. On Wednesday, glacial icefall (serac) triggered a large persistent slab avalanche (size 3). This avalanche occurred on a northeast aspect in the alpine and is suspected to have failed on a crust from early April. This avalanche was only possible with an extremely large load and is not suggestive of general conditions in the region as a whole.

Looking forward, minimal flurries likely won't be enough to form a substantial wind slab problem. Isolated, small but reactive slabs may still form in pockets of leeward terrain.

Snowpack Summary

Light snowfall has begun to bury heavily wind-affected surfaces in exposed terrain, the product of an intense wind event early last week. In sheltered areas, flurries may add to limited stashes of soft snow. A widespread melt-freeze crust can be found 20 to 50 cm deep in most areas, and up to 80 cm in the snowiest parts of the region. This crust is near the surface below 1200 m.

Terrain and Travel

  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
  • Wind slabs are most reactive during their formation.

Problems

Cornices

An icon showing Cornices

Cornices are large this time of year and were likely weakened by recent cold temperatures. Exposure to cornices should be minimized, especially during periods of warm temperatures or strong sun. Give them a wide berth when you are travelling on ridge lines and avoid overhead exposure to large cornices. 

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Wind Slabs

An icon showing Wind Slabs

Light new snow amounts and elevated winds may form small new wind slabs to manage in exposed terrain on Tuesday.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Apr 19th, 2022 4:00PM