Avalanche Forecast

Issued: Feb 25th, 2016 7:50AM

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

rbuhler, Avalanche Canada

Cariboos.

The snowpack is complex and quite variable right now. Buried weak layers remain reactive and conservative terrain selection remains critical.Extra caution is required during the heat of the day, especially on sun exposed slopes and around cornices.

Summary

Confidence

Low - Due to the number and quality of field observations

Weather Forecast

A mix of sun and cloud is expected for Friday with moderate southwest winds in the alpine. A temperature inversion is expected with a layer of above-freezing air sitting around 2000m elevation and colder temperatures in the valleys. A weak storm pulse is expected to bring 5-10cm to the region on Saturday morning. Alpine winds are expected to be moderate from the southwest on Saturday with freezing levels around 1600m. Mostly dry conditions are expected Saturday afternoon through Sunday morning before a second weak storm pulse arrives Sunday afternoon.

Avalanche Summary

On Wednesday, a natural size 3 glide crack avalanche was reported. This released on the ground down 3 meters on a south aspect at 2000m.Â Explosive control trigger five cornice release size 1.5-2.5 on north through east aspects.Â None of these cornice releases triggered slabs.Â On Tuesday, several natural size 1 loose avalanches were reported. Also reported was one natural size 2 loose avalanche from a northwest aspect at 2800m. On Monday, two size 2.5 cornice releases were reported from north aspects.

Snowpack Summary

Surface hoar growth is being reported in sheltered areas as well as near surface faceting. Wind affected surfaces are being reported in the alpine and large cornices are reported to be weak. The surface hoar and/or crust layer from early February is now down 70-90cm and remains reactive in snowpack tests. This layer is expected to become most reactive during the heat of the day, especially on sun exposed slopes.

Problems

Persistent Slabs

A weak layer of surface hoar and/or a crust down 50-90cm remains susceptible to large triggers such as cornice falls or smaller avalanches stepping down. It may be still be possible to directly trigger this layer during the heat of the day.

Minimize exposure to sun exposed slopes when the solar radiation is strong.>Choose conservative lines and watch for clues of instability.>Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 4

Wind Slabs

Lingering wind slabs in the alpine may still be reactive to human-triggers.

Avoid freshly wind loaded features.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Cornices

Large and fragile cornices are will likely continue to fall of ridge crests with sun exposure and temperature fluctuations. Not only are they a hazard in themselves, but also a heavy trigger for slabs on the slope below.

Extra caution needed around cornices with current conditions.>Cornices become weak with daytime heating. >

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 4

Valid until: Feb 26th, 2016 2:00PM