Avalanche Forecast

Issued: Mar 2nd, 2019 4:33PM

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

shorton, Avalanche Canada

Lizard-Flathead.

Cold dry conditions return, and human triggered avalanches remain possible at all elevations.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

SUNDAY NIGHT: Clear, light northeast wind, alpine temperatures drop to -25 C.SUNDAY: Sunny, light northeast wind, alpine high temperature near -18 C.MONDAY: Sunny, light northeast wind, alpine high temperature near -12 C.TUESDAY: Sunny with cloudy periods, light northeast wind, alpine high temperatures near -7 C.

Avalanche Summary

No new avalanches were reported on Saturday. On Friday, numerous natural, human, and explosive triggered storm slabs were reported (size 1-2). Over the previous week, human triggered activity was limited to a few small (size 1) wind slab avalanches on all aspects.

Snowpack Summary

20-40 cm of low density snow is gradually settling and potentially blowing around to form fresh wind slabs in exposed terrain. The snow sits on older wind slabs at upper elevations, which will be difficult to detect now that they are buried. In sheltered areas and below treeline, the new snow sits on facets (sugary snow) and surface hoar (feathery crystals), and on a crust on south-facing slopes.There are potentially three weak layers of surface hoar in the top 100 cm of the snowpack. One is down 30-50 cm, another is down 40-80 cm, and the last one is down 80-110 cm. These layers are most prominent between 1600-1900 m.The lower portion of the snowpack is considered generally strong.

Problems

Wind Slabs

Recent snow is likely forming fresh wind slabs that could be reactive to human triggering at upper elevations.

If triggered, storm or wind slabs may step down to deeper layers resulting in large avalanches.Be cautious as you transition into wind affected terrain.Use caution on open slopes and convex rolls

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Three weak layers of surface hoar may be found in the top metre of the snowpack. They are most prominent between 1600-1900 m, and have been the culprit in recent large avalanches, particularly in openings such as cutblocks, gullies, and slide paths.

Be aware of the potential for wide propagation.Watch for signs of instability such as whumpfing, cracking, or recent avalanches.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 2.5

Valid until: Mar 3rd, 2019 2:00PM