Avalanche Forecast

Issued: Mar 14th, 2018 4:48PM

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

cgarritty, Avalanche Canada

South Coast Inland.

This is the time of year to pay close attention to daytime warming and solar effect. Expect new snow accumulations to become increasingly unstable with any warming on Thursday.

Summary

Confidence

Moderate -

Weather Forecast

Thursday: Mainly sunny. Light southwest winds. Freezing level to around 1500 metres with alpine high temperatures of -4 in the north of the region, slightly warmer in the south.Friday: A mix of sun and cloud. Light northwest or variable winds. Freezing level to 1600 metres with alpine high temperatures of -3 in the north of the region, slightly warmer in the south.Saturday: Cloudy with light flurries beginning in the afternoon, primarily in the south of the region. Light north winds. Freezing level to 1500 metres with alpine high temperatures of -4 in the north of the region, slightly warmer 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 period of light rain, about 5 cm of new snow accumulated on Wednesday. The new snow has buried 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

Light new snow amounts combined with southwest winds have been building small new wind slabs in the lee of exposed terrain at higher elevations. Watch for slabs becoming touchier and loose wet avalanche conditions developing with sun and warming.

Extra caution needed around cornices with current conditions.Use ridges or ribs to avoid pockets of wind loaded snow.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Mar 15th, 2018 2:00PM