Avalanche Forecast

Issued: Mar 16th, 2016 9:39AM

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

jlammers, Avalanche Canada

Cariboos.

As stormy weather tapers-off and a dry ridge builds over the province, solar radiation will become the driver for natural avalanche activity. Watch your overhead hazard as avalanches could travel farther than anticipated.

Summary

Confidence

High

Weather Forecast

A dry ridge of high pressure will develop over the region bringing clear skies for Thursday and Friday. Increased cloud is forecast for Saturday. Ridgetop winds will be light to moderate from the northwest on Thursday morning, and then become light for the rest of the forecast period. Freezing levels will hover around 1200m on Thursday, 1400m on Friday and 1800m on Saturday.

Avalanche Summary

On Monday, 2 sledders were killed in an avalanche near Blue River. We still have very little information about the incident. More details will be made public as they become available. In recent days, a smaller surface avalanche stepped down and triggered a size 3 slab on a southwest facing slope at treeline. The late February surface hoar layer was the likely weak layer associated with this avalanche. This illustrates the potentially touchy and destructive nature of the late February interface. As stormy weather tapers-off and a dry ridge builds over the province, solar radiation will become the driver for natural avalanche activity.

Snowpack Summary

On lee features at treeline and in the alpine light amounts of new snow overlie older wind slabs while intermittent sunny skies have likely promoted a melt-freeze cycle on some sun-exposed slopes. 50-100cm below the surface you'll find a persistent weak layer comprised of surface hoar, facets and/or a thick crust. This layer seems variably reactive. In other words, it's still really touchy in some places while in other spots it's really tough to trigger, and there's not much of a reliable pattern telling us what exact aspects are most suspect. I'd continue to be suspicious of steep, unsupported features at treeline and in the alpine as this layer has the potential for very large avalanches. Below this interface, the snowpack is generally gaining strength. At ridgetop, cornices are huge and could become increasingly touchy with forecast solar radiation.

Problems

Persistent Slabs

The late February layer is becoming less likely to trigger, but it continues to surprise riders with large avalanches. I'd aim for well-supported slopes without convexities, and I'd be increasingly cautious as solar radiation comes into play.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Choose well supported terrain without convexities.>Use conservative route selection, stick to moderate angled terrain with low consequence.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 5

Loose Wet

As the sun comes out, surface avalanche conditions will include a mix of wind slabs in high elevation lee terrain, and pushy loose wet activity on steep, sun-exposed slopes. Loose wet avalanches may also trigger deep and destructive slab avalanches.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>Sluffs may trigger deeper instabilities.>

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Cornices

Daytime warming and solar radiation will promote large cornice failures which could, in turn, trigger a large avalanche on the slope below

Extra caution needed around cornices with current conditions.>Cornices become weak with daytime heating, so travel early on exposed slopes.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 5

Valid until: Mar 17th, 2016 2:00PM