Avalanche Forecast South Columbia

Date Issued: Valid Until:

Avalanche Canada ldreier, Avalanche Canada

Avalanche Forecast

Fri Apr. 12th · 4:01PM

Alpine

Danger Ratings Moderate

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low
Wind Slabs Wind Slabs

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low

Alpine

Danger Ratings Considerable

Treeline

Danger Ratings Moderate

Below Treeline

Danger Ratings Low
Snowfall amounts and timing of the approaching snowstorm are uncertain. As storm totals approach 10 cm moderate to strong southwest winds will likely create new wind slabs.

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

FRIDAY: Clear with cloudy periods / light easterly wind / alpine low -6 C / freezing level 800 mSATURDAY: Cloudy / up to 15 cm snow accumulation / moderate to strong southwest wind / alpine high -5 C / freezing level 1700 mSUNDAY: Cloudy with sunny periods / 5-10 cm snow accumulation / moderate west wind / alpine high -7 C / freezing level 1600 mMONDAY: Mix of sun and cloud / light west wind / alpine high -6 C / freezing level 1700 m

Avalanche Summary

On Thursday no new avalanche activity was observed. On Wednesday no natural avalanche activity was reported. A human triggered wind slab avalanche of size 1.5 on a north aspect at treeline was observed in the south of the region.On Tuesday, several natural and human triggered storm/wind slab avalanches 10-50 cm deep and up to size 2.5 were observed on north and east aspects in the alpine. A size 1.5 explosive triggered cornice did not trigger an avalanche on the northeast facing slope below. Several natural loose wet and wet slab avalanches up to size 2 were reported from southeast, south, west and northwest facing slopes (see a MIN report from Glacier National Park).

Snowpack Summary

The new snow likely falls on a melt-freeze crust on all aspects except for north facing slopes above 2000 m, where the snow stayed dry. Last weeks unsettled weather produced 20-50 cm of snow which is slowly bonding on northern aspects where it might sit on surface hoar (feathery crystals) in some areas.  Older wind slabs sitting on surface hoar might still be sensitive to human triggers.Snowfall amounts taper quickly below treeline. Snow is disappearing rapidly at lower elevations.

Problems

Wind Slabs

Wind Slabs

Moderate to strong southwest winds will transport the new snow and create wind slabs during the day. Older wind slabs can be found in immediate lee features in the alpine and might still be sensitive to human triggers.

Be careful with wind-loaded pockets, especially near ridge crests and roll-overs.Watch for signs of instability such as whumpfing, or cracking.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2