Avalanche Forecast

Issued: Mar 4th, 2019 4:55PM

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

shorton, Avalanche Canada

Lizard-Flathead.

Persistent slab avalanches continue to pose a low likelihood, high consequence problem at lower elevations.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

MONDAY NIGHT: Clear, light northeast wind, alpine temperatures drop to -15 C.TUESDAY: Sunny, light southeast wind, alpine high temperatures near -8 C.WEDNESDAY: Cloudy with isolated flurries, trace accumulations, light southeast wind with moderate gusts, alpine high temperatures near -10 C.THURSDAY: Scattered flurries with 5-12 cm of snow, 30-50 km/h southwest wind, alpine high temperatures near -4 C.

Avalanche Summary

On Monday, one small (size 1) skier triggered slab avalanche was reported on an east aspect at 1850 m. A few small (size 1) wind slab avalanches and loose dry sluffs were reported over the weekend.

Snowpack Summary

Sheltered areas have 20-40 cm of low density snow on the surface while exposed terrain has been wind affected. Sun crusts can be found on the surface on south-facing slopes. There are potentially three layers of surface hoar in the upper snowpack. One is down 30-50 cm, another is down 40-80 cm, and the last one is down 80-120 cm. These layers have been most prominent and reactive between 1600 and 1900 m over the past month. The lower portion of the snowpack is generally strong.

Problems

Persistent Slabs

Buried surface hoar layers have been a problem at lower elevations over the past month. Although the likelihood of triggering these layers has decreased, this problem still warrants conservative travel in steep open terrain.

Watch for whumpfing, hollow sounds, and shooting cracks.Use caution on open convex rolls at and below treeline where buried surface hoar may be preserved.Be aware of the potential for wide propagation.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Wind Slabs

Wind slabs could be reactive to human triggering at upper elevations.

Use ridges or ribs to avoid pockets of wind loaded snow.Avoid freshly wind loaded features.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 1.5

Valid until: Mar 5th, 2019 2:00PM