Avalanche Forecast

THURSDAY NIGHT: Cloudy with some scattered flurries and up to 5 cm of new snow, strong southwest wind, freezing level drops to 1000 m.

FRIDAY: Cloudy with scattered flurries and 5-10 cm of new snow, strong south wind, freezing level climbs to 1700 m with treeline temperatures around -2 C.

SATURDAY: Another 5 cm of new snow by the morning then a mix of sun and cloud during the day, light southwest wind, freezing level climbs to 1400 m with treeline temperatures around -5 C.

SUNDAY: Cloudy with some isolated flurries, light south wind, freezing level around 1200 m with treeline temperatures near -5 C.

Given the lack of recent field observations we remain uncertain about the likelihood of persistent slab avalanches. Since there was significant activity on these layers between Feb 23-28 (see below), we recommended remaining cautious because these types of weaknesses can take a long time to heal. Only consider pushing into steeper avalanche terrain if you are equipped to rule out the possibility of deeper weak layers in your local riding area.

Also, ongoing wind has likely formed wind slabs in steep high elevation terrain.

Some of the notable avalanche activity that has us concerned include:

• A very large (size 3.5) persistent slab avalanche that likely occurred on Feb 28 just north of the region in the McGregors, likely triggered by a smaller wind slab avalanche (MIN report).
• A natural size 2.5 avalanche that ran full path in the Dore River area on Feb 25 (MIN report).
• A very large human-triggered avalanche near Valemount on Feb 23 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.
• A fatal avalanche just outside of the region, northeast of Valemount, in Swift Creek on Feb 23. 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.

On Friday, 10-15 cm of new snow will fall on firm interfaces that formed during Thursday's warm up including crusts and moist snow. High shaded terrain will have a mix of soft and hard wind slabs.

Over the past few weeks there have been multiple deeper weak layers producing large avalanches, but we have little to no information about how these layers have trended over the past few days. Layers of concern include a 50-100 cm deep layer of facets that was buried in mid-February, a 50-150 cm deep layer of surface hoar from early February that was most prevalent at treeline (and existed as a facet/crust combination on steep south-facing terrain), and finally another persistent weak layer from late January that is now roughly 100-150 cm deep. Based on recent weather the likelihood of triggering these layers was probably elevated during the warm weather, but will gradually become less likely as temperatures cool.

• Use conservative route selection and resist venturing out into complex terrain.
• Be aware of the potential for large avalanches due to the presence of buried persistent weak layers.
• Remote triggering is a concern, avoid terrain where triggering slopes from below is possible
• Be especially cautious as you transition into wind affected terrain.