Avalanche Forecast

Issued: Mar 17th, 2018 3:53PM

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

mgrist, Avalanche Canada

Northwest Coastal.

Expect to find lingering wind slabs at high elevations and wet snow at low elevations, especially if the sun comes out for any length of time.

Summary

Confidence

High - The weather pattern is stable

Weather Forecast

Not much change in the weather pattern: A mix of sun and increasing cloud and little if any precipitation until Tuesday.SUNDAY: Partly cloudy / Light northerly winds / Alpine temperature +1 C / Freezing level 1400 m.MONDAY: Cloudy with isolated flurries / Light to moderate north westerly winds / Alpine temperature near 0 degrees C / Freezing level 1200 m.TUESDAY: Scattered flurries (5-10 cm possible) / Moderate westerly winds / Alpine temperature near 0 degrees C / Freezing level 700 m.

Avalanche Summary

Over the past three days, several wet loose avalanches were observed at tree line and below, primarily on sunny aspects. Some of these stepped down to basal facets in northern parts of the region.On Friday, a remote-triggered size 2 persistent slab was reported near Stewart, running on an east facing rib feature near 1600m. The slab (30-120cm thick) failed on the mid January layer, with surface hoar 4-8mm reported.

Snowpack Summary

Recent warming has melted and refrozen the snow surface at higher elevations. Expect the snow surface to be wet or a melt-freeze crust on all aspects except for possibly high elevation north facing. Strong easterly to southerly winds have redistributed any available soft snow and produced variable surfaces at high elevations, including wind slabs in lee and cross-loaded features. This overlies a sun crust on solar aspects and 5 to 20 mm surface hoar on sheltered, shady aspects at all elevation bands.Beneath this, layers of crusts, facets, and isolated surface hoar buried 50 to 100 cm exist below the surface from mid- and late-February. A surface hoar and crust layer from January is buried around 150 to 200 cm.Near the bottom of the snowpack, sugary facets exist in colder and dryer parts of the region, such as the far north.

Problems

Wind Slabs

Isolated wind slabs may linger in lee features. These slabs overly a weak surface hoar layer in parts of the region, which have produced wide propagations and fast-moving avalanches.

Approach lee and cross-loaded slopes with caution.Avoid steep, rocky, and wind affected areas where triggering slabs is more likely.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2.5

Loose Wet

Mid-mountain freezing levels (and a possible lack of overnight re-freeze) will mean that loose wet avalanches are more likely at lower elevations. Use caution in terrain features where a small avalanche could have serious consequences.

Watch for signs that the snow is moistening such as pin-wheeling and point-releases below cliffs.Avoid terrain traps such as gullies and cliffs where small avalanches can have high consequence.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Mar 18th, 2018 2:00PM