Avalanche Forecast

Issued: Mar 10th, 2014 9:51AM

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

rbuhler, Avalanche Canada

South Coast.

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

Summary

Confidence

Fair

Weather Forecast

A ridge of high pressure will dominate conditions for Tuesday and Wednesday before breaking down on Thursday. There is some wx model uncertainty regarding freezing levelsTuesday: Mostly sunny, freezing level 500-800m overnight, 1300-1600m afternoon, ridgetop winds light W-NWWednesday: Mostly sunny, freezing level 500-1000m overnight, 2000m+ afternoon, ridgetop winds 30-50 km/h SWThursday: A mix of sun and cloud, freezing level 800-1200m overnight, 1500-1800m afternoon, ridgetop winds light SW

Avalanche Summary

On Sunday, we received reports of natural slab avalanche activity in the alpine. Natural cornice releases also produced avalanches up to size 3. Also reported were two ski-cut wind slab avalanches size 1-2.

Snowpack Summary

Coquihalla and south: Recent mild temperatures have resulted in rain to ridgetop 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.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - 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.>Cornices become weak with daytime heating. >

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Valid until: Mar 11th, 2014 2:00PM