Avalanche Forecast

Issued: Apr 11th, 2019 4:30PM

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

ldreier, Avalanche Canada

North Columbia.

As soon as the sun comes out the surface snow will become moist and increase the likelihood of loose wet avalanches. Wind slabs might still be sensitive to human triggering.

Summary

Confidence

High -

Weather Forecast

THURSDAY NIGHT: Cloudy with clear periods / light easterly wind / freezing level 400 mFRIDAY: Sunny with cloudy periods and isolated flurries / light to moderate westerly wind / alpine high temperature -5 C / freezing level 1800 mSATURDAY: Cloudy / up to 15 cm of snow accumulation / strong southwest wind / alpine high temperature -5 C / freezing level 1600 mSUNDAY: Cloudy / up to 5 cm of snow accumulation / light to moderate westerly wind / alpine high temperature -7 C / freezing level 1500 m

Avalanche Summary

On Wednesday the avalanche activity decreased. A few natural and human triggered wind/storm slab avalanches up to size 2 were reported on west and north aspects at treeline and in the alpine. On Tuesday, several natural and human triggered storm/wind slab avalanches 20-40 cm deep and up to size 2.5 were observed on north and east aspects. Two of these were remotely triggered, one by humans and another one by a helicopter. A layer of small surface hoar below the most recent snow may have been the weak layer. Several natural wet slab and loose wet avalanches up to size 2.5 were reported from south and west aspects (see a MIN report from Glacier National Park).

Snowpack Summary

Last weeks unsettled weather produced 30-50 cm of snow that sits on a melt-freeze crust on all aspects except for north slopes above 2000 m, where it sits on dry snow and surface hoar (feathery crystals) in some areas. On northern aspects the new snow is slowly bonding and humans might still trigger wind slab avalanches. Recent snowfall amounts taper quickly below treeline. Snow is disappearing rapidly at lower elevations.

Problems

Loose Wet

As soon as the sun is coming out the snow surface will become moist and increase the likelihood of loose wet avalanches on sun exposed slopes.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Minimize overhead exposure to cornices above.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Wind Slabs

Up to 50 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 surface hoar in isolated locations. Wind slabs in lee features may remain reactive to human triggers.

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

Aspects: North, North East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 12th, 2019 2:00PM