Avalanche Forecast

Issued: Jan 17th, 2018 4:35PM

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

jmcbride, Avalanche Canada

South Coast.

A wet, wild winter storm system with heavy precipitation, strong winds and mild temperatures is increasing the avalanche hazard. Avoid areas that receive heavy loading from snow and wind until the new snow has had a chance to settle.

Summary

Confidence

Moderate - Freezing levels are uncertain

Weather Forecast

TONIGHT: Wet snow. Accumulation 20-30 cm. Ridge wind extreme, southwest. Temperature 2. Freezing level lowering to 1100 m.THURSDAY: Snow. Accumulation 30-40 cm. Ridge wind strong, southwest. Temperature near 0. Freezing level 1000 m.FRIDAY: Snow. Accumulation 20-30 cm. Ridge wind moderate, southwest. Temperature near 0. Freezing level 1000 m.SATURDAY: Snow increasing. Accumulation 20-30 cm. Ridge wind light to moderate, southwest. Temperature near 0. Freezing level 900 m.

Avalanche Summary

Last Tuesday a skier was injured in a loose, wet avalanche on the North Shore mountains when the top 10-15 cm of wet snow released on the January 8th crust. On Friday explosive control produced a size 1 avalanche that released a 45 cm thick slab on a weak layer just above the January 7th crust.

Snowpack Summary

At upper treeline and alpine elevations about 10- 20 cm of new snow has fallen and now covers the January 16th crust. Near treeline and below, rain has soaked the upper snowpack which consists of 15-20 cm of wet snow above three prominent crusts (January 10th, January 8th and January 7th) from recent warm weather and rain events. The most notable layer is the January 7th rain crust, which is now buried 40-60 cm deep. The snowpack depth at 1000 m is about 150 cm and many early season hazards are still present.

Problems

Storm Slabs

New snow combined with strong southerly winds will form touchy storm slabs particularly at upper treeline and alpine elevations. These slabs overlie a recent melt-freeze crust and will continue to build with more snow and wind in the forecast.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Loose Wet

At lower elevations where rain has soaked the upper snowpack making loose wet and wet slab avalanches possible in steep, unsupported terrain or convex rolls.

Use extra caution on slopes if the snow is moist or wet.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 - 2

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