Avalanche Forecast

Issued: Apr 10th, 2019 4:13PM

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

jsmith, Avalanche Canada

Cariboos.

Wind slabs may remain reactive to human triggers; especially in high elevation, north facing terrain that is steep, rocky, and/or has a highly variable snowpack depth.

Summary

Confidence

High -

Weather Forecast

WEDNESDAY NIGHT: Cloudy with isolated flurries; 3-10 cm. / Light, southwesterly winds / Alpine low -5 C / Freezing level 1000 m.THURSDAY: Mostly cloudy with isolated flurries; trace-3 cm. / Light, northwesterly winds / Alpine high -4 C / Freezing level 1500 m.FRIDAY: Mix of sun and cloud / Light, southerly winds / Alpine high -3 C / Freezing level 1700 m.SATURDAY: Snow in the mountains and rain in the valleys; 3-5 cm. / Light to moderate, southwesterly winds / Alpine high -3 C / Freezing level 1600 m.

Avalanche Summary

On Tuesday, a small (size 1) slab avalanche 30 cm. deep was remotely triggered by a skier from 80 m. away on a northeast aspect at 2250 m. A layer of small surface hoar below the most recent snow may have been the weak layer. Additionally, several loose wet avalanches up to size 1.5 where triggered on solar aspects throughout the day by strong solar radiation.On Monday there was quite a bit of natural avalanche activity in the recent storm snow. Slabs to size 1.5 were reported from all aspects between 1800 and 2700 m. The natural activity was likely caused by the appearance of the strong April sun.On Sunday wind slabs to size 2 released naturally and were also susceptible to human triggering on north, northeast and east facing terrain between 1900 and 2200 m.

Snowpack Summary

Last week's unsettled weather produced 15-30 cm of snow in the alpine which tapers rapidly with elevation. This snow is sitting on a melt-freeze crust on all aspects except for northerly slopes above 1800 m, where it sits on dry snow and possibly small surface hoar (weak, feathery crystals) in isolated locations. I suspect high elevation, north facing terrain where wind slabs may be sitting on small surface hoar would currently be the most likely place to trigger a slab avalanche.Snow is disappearing rapidly at lower elevations.

Problems

Wind Slabs

Up to 30 cm of snow sits on a crust in most locations, except for high elevation, north facing terrain where the old snow surface remained dry with small surface hoar in isolated locations. These wind slabs may remain reactive to human triggers.

Wind slabs that are sitting on surface hoar may remain reactive to human triggers.Steep, rocky terrain with a highly variable snowpack depth are likely places to trigger these slabs.Pay attention to changing condition with elevation/aspect.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Loose Wet

Any appearance of the strong April sun can initiate a loose wet avalanche cycle. The likelihood of loose wet avalanches increases as temperatures warm through the day and/or if the sun comes out for a prolonged period of time.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.Loose wet avalanches may start small but they can grow and push you into dangerous terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Apr 11th, 2019 2:00PM