Avalanche Forecast

Issued: Jan 18th, 2015 8:50AM

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

jlammers, Avalanche Canada

Cariboos.

Touchy conditions are expected, especially at higher elevations. Check out the most recent Forecaster Blog for more details on the current conditions. http://www.avalanche.ca/blogs/VLsBsCgAACYAJdfM/mid-jan-sh

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

Unsettled conditions and light flurries are expected on Monday as a pacific frontal system exits the region to the southeast. By Tuesday a weak dry ridge of high pressure will rebuild. Confidence in the forecast for Wednesday gets shaky on Wednesday as weather models disagree on the ridge's ability to deflect a system creeping in from the northwest. Stay tuned! On Monday, ridgetop winds are expected to be moderate from the west, dropping to light from the northwest on Tuesday and Wednesday. Freezing levels should hover around 1400m on Monday, and then drop to near valley bottom for Tuesday and Wednesday.

Avalanche Summary

Natural and human-triggered wind slab activity to size 1.5 was observed in response to new snow and wind on Friday night. With more snow and wind on Sunday, I'm sure the developing storm slab has increased in size and reactivity. In sheltered terrain where the new snow is less consolidated, I would expect fairly widespread loose dry avalanche activity in steep terrain. In isolated terrain, a surface avalanche in motion may also "step down" to a deeper, more destructive weak layer which was buried in mid-December.

Snowpack Summary

Up to 35cm of new snow has fallen since Friday night. The new snow, which has been distributed into deeper deposits in higher wind-exposed terrain, overlies widespread 5-15mm surface hoar and a sun crust on steep sun-exposed slopes. The problematic mid-December surface hoar/crust layer is typically down 50-90cm below the surface and continues to produce clean shears at and below treeline. Although less likely to trigger, I'd continue to treat this layer with respect and suspicion as an avalanche at this interface may have nasty consequences.

Problems

Storm Slabs

New snow and wind on Sunday will add size and reactivity to a developing storm slab. The new snow is expected to be especially reactive due to underlying weak crystals. In sheltered terrain, expect loose dry avalanche activity.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>The new snow will require several days to settle and stabilize.>Be cautious as you transition into wind affected terrain.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

New snow and wind may spark renewed activity on weak crystals buried in mid-December. Although less likely to trigger, avalanches at this interface could be destructive in nature.

Use conservative route selection, stick to moderate angled terrain with low consequence.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Jan 19th, 2015 2:00PM