Avalanche Forecast

Issued: Apr 15th, 2018 3:53PM

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

jsmith, Avalanche Canada

Lizard-Flathead.

New snow and wind on Monday will create touchy storm slabs reactive to human triggers; especially in wind effected terrain.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

MONDAY: Snow, accumulation 10-20 cm. Moderate to strong easterly ridgetop winds. Alpine temperature -1. Freezing level around 1500 m.TUESDAY: Snow, accumulation 5-10 cm. Moderate southwesterly ridgetop winds. Alpine temperature -1. Freezing level around 1500 m.WEDNESDAY: Mostly cloudy with sunny breaks. Light southwesterly ridgetop winds. Alpine temperature +1. Freezing level rising to around 1700 m.

Avalanche Summary

Several loose wet avalanches up to size 2.5 which were triggered by cornice falls were reported near Fernie on Sunday. Storm slab avalanche activity will likely increase with the forecast snow on Monday.

Snowpack Summary

15-25 cm of new snow and moderate winds have formed storm slabs reactive to human triggers. This storm snow overlies numerous crusts in the upper 100 cm of the snowpack.The mid-pack is generally well settled and strong.A layer of sugary facets around a crust can be found near the bottom of the snowpack which has been dormant for some time. Large triggers, such as a falling cornice, or a major warm-up to the snowpack could trigger this layer.

Problems

Storm Slabs

Snow and wind on Monday will create touchy storm slabs reactive to human triggers.

Use caution when transitioning into wind effected terrain.Watch for signs of instability such as whumphing, cracking, or recent natural avalanching.Use small slopes with low or no consequence to test the bond of the new snow.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Loose Wet

When the sun comes out it will quickly weaken the new snow and cause loose wet avalanching on steep solar slopes.

Watch for signs that the snow is heating up such as pin-wheeling or the surface snow becoming moist.Minimize exposure to sun exposed slopes when the solar radiation is strong.Cornices become weak with daytime heating. Give them a wide berth both from above and below.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Apr 16th, 2018 2:00PM