Avalanche Forecast

TUESDAY NIGHT: Mostly cloudy with scattered flurries and up to 5 cm of snow, moderate to strong southwest wind, treeline temperatures drop to -8 C.

WEDNESDAY: Mix of sun and cloud with some isolated flurries, moderate to strong southwest wind, freezing level climbs to 1300 m with treeline temperatures around -5 C.

THURSDAY: Mix of sun and cloud, strong south wind, freezing level climbs to 1600 m with treeline temperatures around -3 C.

FRIDAY: Cloudy with scattered flurries and 5-10 cm of new snow, strong south wind, freezing level climbs to 1600 m with treeline temperatures around -3 C.

Although there have been limited recent field observations, we have good reason to remain suspect of persistent weak layers producing large destructive avalanches.

On Sunday, there was a report of a size 2 human-triggered wind slab avalanche in the east of the region (MIN report). This MIN report from just north of the region in the McGregors shows a very large (size 3.5) persistent slab avalanche that likely occurred on Sunday as well. This avalanche was triggered by a smaller wind slab on an east aspect.

Last week there were several reports of large (size 2-3.5) natural and human triggered avalanches across the region. Some notable ones included:

• A natural size 2.5 avalanche that ran full path in the Dore River area on Thursday (MIN report)
• A very large human-triggered avalanche on Tuesday near Valemount that was initiated from a wind-loaded start zone at the top of a large alpine feature. It propagated for hundreds of meters along a ridge and ran to valley bottom. Thankfully the rider was able to escape unharmed.
• Also on Tuesday (Feb 23), there was a fatal avalanche just outside of the region, northeast of Valemount, in Swift Creek. The avalanche was a size 3.5 and is suspected to have failed on the late January persistent weak layer. The report can be found here.

So although there have been limited recent observations, the size and nature of recent avalanches still has us concerned about persistent problems.

The snowpack in the Cariboos is currently complex, with multiple persistent weak layers. 

There is about 50-100 cm of snow sitting on a persistent weak layer of facets that was buried in mid-February.

There is now 80-180 cm of snow above another persistent weak layer from early February which is composed of surface hoar. This layer is most prevalent at treeline and below treeline. On steep south-facing terrain, this layer may consist of facets on a sun crust. 

Yet another persistent weak layer from late January exists down 90-200 cm. There have been very few recent reports of avalanches on this layer, however, there have been several large avalanches on this layer in the neighboring North Rockies region recently. Recent test results also suggest that this layer is still a serious concern, and will propagate widely if triggered.

• Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
• Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
• If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
• Avoid freshly wind loaded terrain features.