Avalanche Forecast

Issued: Feb 23rd, 2019 4:58PM

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

mbender, Avalanche Canada

Lizard-Flathead.

Expect to continue to see reactive storm slabs on Sunday with the 50-60 cm of new snow that fell Friday night.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

SUNDAY: Sunny with cloudy periods / moderate east wind / alpine temperature -15MONDAY: A mix of sun and cloud / light to moderate east wind / alpine temperature -17TUESDAY: A mix of sun and cloud / light northeast wind / alpine temperature -15

Avalanche Summary

Numerous natural and explosives triggered storm slab avalanches to size 2 and 2.5 were reported on Saturday. These were 50-100 cm deep running on east through north aspects in the alpine and treeline.An explosive triggered a large (size 2.5) persistent slab avalanche on Thursday. It was on a southerly aspect and between 1650 and 2000 m. The slab was about 40 cm deep.

Snowpack Summary

Up to 60 cm of low density new snow sits on wind affected surfaces in the alpine and treeline. In sheltered areas, the new snow is burying faceted surface snow and possibly a layer of surface hoar. In sheltered areas between 1600 and 1800 m, another weak layer of surface hoar crystals buried around Valentines Day, is now 60-80 cm below the snow surface.Two more weak layers of surface hoar may be found within the snowpack. One buried early-February, is 80-100 cm deep in shaded and sheltered areas above 1600 m. The other buried mid-January, is 100-150 cm down and is most prominent between 1600 m and 1900 m.The remainder of the snowpack is well-settled.

Problems

Storm Slabs

Up to 60 cm of low density new snow fell Friday night. Expect this new snow to continue to be reactive as a storm slab as it settles.

If triggered, storm or wind slabs may step down to deeper layers resulting in large avalanches.The new snow will require several days to settle and stabilize.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

Two weak layers of surface hoar may be found between 1500 m and 1900 m, around 80-120 cm deep in the snowpack. These layers have been the culprit of recent large avalanches, particularly in openings such as cutblocks, gullies, and slide paths.

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

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Feb 24th, 2019 2:00PM