Avalanche Forecast

Issued: Mar 9th, 2014 8:46AM

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

Peter, Avalanche Canada

South Coast.

Strong solar radiation and rising temperatures could trigger natural avalanche activity on south facing slopes during the day.

Summary

Confidence

Fair

Weather Forecast

Monday: Cloudy with possible flurries early followed by sunny breaks. The freezing level is around 1400 m. Winds are light from the W-NW. Tuesday: A mix of sun and cloud. The freezing level climbs from 1000 m in the morning to 1700 m in the afternoon. Winds are light and variable. Wednesday: A mix of sun and cloud. Temperatures should climb even higher with the freezing level as high as 2500 m. Winds are light from the SW.

Avalanche Summary

Several skier controlled slab avalanches up to size 2 were reported on Saturday. Most of these were within the recent storm snow and many propagated quite widely. There was also a report of a very large natural slab avalanche from a north aspect near the Coquihalla. This avalanche may have occurred during the last storm on Thursday. Heavy snow and strong winds on Saturday night probably kicked off another fairly widespread avalanche cycle.

Snowpack Summary

Coquihalla and south: Recent mild temperatures have resulted in rain to ridge top in many areas. It's likely that the upper snowpack below 1700-1800 m is saturated and/or contains several melt-freeze crusts. The early March melt-freeze crust is down 60-100 cm depending on elevation. There are no new snowpack tests on this layer to report; however, continued loading and mild temps should help stabilize this previous weak layer. Duffey Lake and north: Around 25-35 cm of new snow fell on Saturday night, with strong southerly winds and freezing levels jumping between 1400 and 1700 m. It's The early March melt-freeze crust is down 60-80 cm on north aspects up to 1800 m and south aspects up to 2200 m. The mid Feb weak layer is generally now found down 90-130 cm. Recent snowpack tests continue to give popping shears where this layer is less than 100 cm deep. Deeply buried weak layers of facets and depth hoar remain a concern on high alpine slopes with thin or variable snow cover.

Problems

Storm Slabs

Weaknesses may exist within or under the recent storm snow. Expect dense wind slabs in exposed Northwest through East facing terrain at and above treeline.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Persistent Slabs

Persistent slabs are a greater concern in northern sections where old weak layers can be found in the upper 120 cm of the snow pack. There's potential for heavy loads like a falling cornice or a smaller avalanche to step down to these layers.

Be aware of the potential for large, deep avalanches.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Cornices

Cornices have probably grown quite large during the last few storms. Strong sunshine and rising temperatures later this week could cause them to start popping off.

Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Mar 10th, 2014 2:00PM