Avalanche Forecast

Issued: Mar 16th, 2014 11:14AM

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.

ghelgeson, Avalanche Canada

Cariboos.

Summary

Confidence

Fair

Weather Forecast

Synopsis: Snowfall should taper late Sunday as the flow dries, cools & shifts to the NW. Some weak ridging builds in for Monday and Tuesday. The models show a timid system set to arrive late Tuesday night.Sunday Night: Freezing Level: 1400m lowering to 700m; Precipitation: 1:3mm - 1:10cm (locally heavy convective snowfall possible); Treeline Wind: Mod, SW switching NW overnight | Strong NW at ridgetopMonday: Freezing Level: 400m; Precipitation: Trace; Treeline Wind: Light, NW | Moderate NW at ridgetopTuesday: Freezing Level: 500m rising to 1100m; Precipitation: Nil; Wind: Moderate, NWTuesday Night/Wednesday: Freezing Level: 1100m - 1600m; Precipitation: 4:8mm - 4:10cm; Treeline Wind: Moderate, SW | Strong SW at ridgetop

Avalanche Summary

No new avalanche activity to report from Saturday.A group of sledders triggered a large avalanche not far from Blue River on Friday resulting in one fatality. Some information is available here.On Friday we received numerous reports of small soft slabs running on the March 13 Surface Hoar/Crust combo.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

The storm came in warm and produced 10 - 30 cm of snow that is now resting on the old surface which consists of mix of 3 - 6mm surface hoar and crust.Last weeks storm snow has settled into a 50cm - 80cm slab that rests on the early March interface consisting of small grained surface hoar in sheltered areas and a sun crust on solar aspects. Ridgetop cornices remain large and unsupported.The February 10th surface hoar/facet/crust combo is 90cm - 160cm below the snow surface and widespread throughout the region. Surface avalanches in motion and cornice fall still have the potential to initiate an avalanche on this deeply buried weak layer. Remote triggering on this layer is ongoing. The mid and lower snowpack are strong and well consolidated.

Problems

Storm Slabs

The storm came in warm which should allow the 10 - 30 cm of new snow to settle and bond to the Mid March crust/surface hoar interface over the next few days. Watch for wind slab development immediately lee of ridge crest.

Be cautious of sluffing.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

The early March suncrust/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.

The trees are not the safe-haven they normally are at this time. Terrain at treeline is primed for human triggered avalanches. >Given all the uncertainty surrounding this slab, I advise against stepping out into terrain with any kind of consequence.>Watch for terrain traps where avalanche debris can accumulate into deep deposits.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

3 - 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.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

3 - 6

Valid until: Mar 17th, 2014 2:00PM