Avalanche Forecast

Issued: Mar 13th, 2018 4:59PM

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

Avalanche Canada cgarritty, Avalanche Canada

Improved stability is expected with cooling temperatures on Wednesday. Keep your guard up at high elevations where recent warming had less of a stabilizing effect.

Summary

Confidence

Moderate -

Weather Forecast

Wednesday: Cloudy with scattered flurries continuing from Tuesday night, bringing 5-10 cm of new snow by end of day. Light to moderate southwest winds. Freezing level to 1500 metres with alpine high temperatures around -3.Thursday: A mix of sun and cloud. Light northeast winds. Freezing level to 1600 metres with alpine high temperatures around -3 in the north of the region, slightly warmer in the south.Friday: Mainly cloudy. Light north winds. Freezing level to 1700 metres with alpine high temperatures around -3 in the north of the region, closer to -1 in the south.

Avalanche Summary

A report from Monday showed one size 1.5 wind slab that released with skier traffic on a steeper north aspect (near ridgecrest) in the alpine near Birkenhead Lake. Several solar triggered loose wet releases were reported, averaging size 1.5-2 but reaching size 3 in isolated areas.Reports from Sunday show primarily solar induced avalanches size 1.5-2 on south and west facing sun exposed slopes during the heat of the day. On Saturday a skier triggered size 2 wind slab avalanche was reported from the north of the region on a northeast aspect in the alpine. There was also a report of natural size 2 wind slab avalanche on a northwest aspect in the alpine. Avalanche activity on Friday was reported as either loose dry to size 1 or wind slab activity to size 1-1.5 on northerly aspects at tree line.

Snowpack Summary

After a bout of light rain, light new snow amounts are expected to accumulate on the surface on Wednesday. The new snow is falling on older storm snow that was redistributed by southerly winds at upper elevations and affected by above freezing temperatures. Some high (above 1800m) north-facing slopes may have escaped the warming. The older storm snow sits on a sun crust on steep south-facing slopes, cold dry snow and possibly small surface hoar on shady aspects.In the north of the region a weak layer buried in mid-February is about 40-50 cm below the surface and has been reactive in some snowpack tests. The layer is composed of sugary facets, a sun crust on solar aspects, and surface hoar that is present at and below treeline. The snowpack is well settled in the south of the region around the Coquihalla and in Manning Park.Variable winds in the past month have created cornices on many alpine ridgelines. They become touchier as temperatures rise and with the strong late winter sun on clear days.

Problems

Wind Slabs

An icon showing Wind Slabs
Recent snow combined with predominantly southwest winds have created wind slabs in the lee of exposed terrain features at alpine elevations. Light new snow may create thin new wind slabs to manage on Wednesday.
Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.Extra caution needed around cornices with current conditions.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 14th, 2018 2:00PM