Avalanche Forecast

Issued: Mar 8th, 2014 7:27AM

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

Peter, Avalanche Canada

South Coast.

Summary

Confidence

Fair - Forecast snowfall amounts are uncertain

Weather Forecast

Tonight and Sunday: Moderate to heavy snowfall overnight (10-15 cm north and 20-30 cm south) drying out during the day. Expect a mix of sun and cloud Sunday. The freezing level should peak around 1400-1600 m. Winds are moderate to strong from the W-SW. Monday: Cloudy with sunny breaks and possible flurries. The freezing level is around 1200 m. Winds are light to moderate from the west. Tuesday: A mix of sun and cloud. The freezing level is around 1400 m and winds are light and variable.

Avalanche Summary

There were no new reports from Friday. Forecast heavy precipitation, strong winds, and high freezing levels are all reasons to expect another natural avalanche cycle late on Saturday and possibly into Sunday morning. Natural activity should taper off over the next day or two as conditions dry out.

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: New dense wind slabs are likely in exposed NW-E facing terrain and cross-loaded features. It seems like the snow line creeped up to 1700-1800 m resulting in moist snow below. The early March melt-freeze crust can be found down 40-60 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 70-120 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 new storm snow. Expect dense wind slabs to build in exposed Northwest through East facing terrain at and above treeline.

Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very 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 meter of the snow pack. New loading from snow and wind, or a smaller avalanche could be enough to produce a very large avalanche.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.>Be aware of the potential for large, deep avalanches.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Loose Wet

Rain at lower elevations will likely saturate the upper snowpack. We could also see the sun come out on Sunday, kicking off a loose wet cycle on solar aspects.

Avoid sun exposed slopes when the solar radiation is strong, especially if 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.

Likelihood

Likely

Expected Size

1 - 3

Valid until: Mar 9th, 2014 3:00PM