Avalanche Forecast

Issued: Mar 17th, 2014 8:43AM

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

Peter, Avalanche Canada

Cariboos.

Summary

Confidence

Fair

Weather Forecast

Tuesday: Mainly cloudy with a chance of flurries â€“ around 5 cm. The freezing level is around 1300 m. Ridge winds are moderate from the W-SW. Wednesday: Periods of snow â€“ 5-10 cm. The freezing level is near 1000 m and ridge winds are moderate from the West. Thursday: Cloudy with flurries. The freezing level is around 800-1000 m and ridge winds are light.

Avalanche Summary

Several fresh wind slabs were easily triggered by skiers on the weekend, particularly where the new snow was sitting on a sun crust. There was also a report of a large explosive triggered avalanche from steep rocky terrain that likely released on the Feb. 10 persistent weak layer.A group of snowmobilers triggered a large avalanche not far from Blue River on Friday resulting in one fatality. Some information is available here.The group involved in a very close call with a size 3.5 avalanche in the Ozalenka Valley south of McBride submitted a great incident report. Check it out here. It's an excellent example of the kind of activity we've been seeing throughout the interior in the last week.

Snowpack Summary

Around 30-40 cm of recent storm snow has fallen in the past few days. Periods of strong westerly winds have probably formed fresh wind slabs in exposed lee and cross-loaded terrain. This new snow now sits on the previous snow surface which consists of surface hoar and/or crust.A couple other notable persistent weaknesses remain a concern in the mid-snowpack. Another surface hoar/sun crust combo buried in early March is now down around 60-80 cm. The February 10th surface hoar/facet/crust combo is 100cm - 150cm below the snow surface and widespread throughout the region. Surface avalanches in motion and cornice fall have the potential to initiate an avalanche on this deeply buried weak layer.

Problems

Storm Slabs

Weaknesses may still exist within or under the recent storm snow. Expect fresh dense wind slabs in exposed NW-SE slopes at and above treeline, and in cross-loaded terrain features.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

The early March sun crust/ surface hoar combo should not be underestimated. While there's a lot of uncertainty and complexity surrounding this layer, it's important to note that human triggering is most likely at treeline.

Watch for terrain traps where avalanche debris can accumulate into deep deposits.>The trees are not the safe-haven they normally are at this time. Terrain at treeline is primed for human triggered avalanches. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Deep Persistent Slabs

The early February Persistent Weak Layer is still active and has produced some stunning avalanches recently. Very large avalanches may result from a surface avalanche in motion, a cornice fall or a rider finding the sweet spot.

Avoid rock out croppings, large convexities and anywhere the snowpack is thin and/or variable.>Be aware of the potential for large, deep avalanches due to the presence of deeply buried weak layers.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Mar 18th, 2014 2:00PM