Avalanche Forecast
Issued: Dec 25th, 2019 2:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
ghelgeson,
Avalanche Canada
Natural avalanche activity has waned, but a persistent slab 40 to 100 cm in depth remains very much in play. You can't feel a problem like this under your track or skis, the only way to manage this is to stick to relatively simple terrain free of overhead hazard.
Summary
Confidence
Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.
Weather Forecast
The most recent weather model runs are showing very little precipitation through the end of the year aside from small dribs and drabs. Looks like the wind will begin to pick up out of the south/southwest on Thursday.
WEDNESDAY NIGHT: Freezing level at valley bottom, light northwest wind, no significant precipitation expected.
BOXING DAY: Clear skies at dawn with increasing cloud cover throughout the day, overcast by sundown. Freezing level at valley bottom, moderate to strong south/southwest wind, trace of snow possible during the day, potential for 2 to 6 cm by Friday morning.
FRIDAY: Broken cloud cover, freezing level at valley bottom, moderate to strong west/southwest wind, trace of snow possible during the day.
SATURDAY: Scattered cloud cover at dawn building to overcast by sundown, freezing level at valley bottom, strong southerly wind, no precipitation expected.
Avalanche Summary
There is a notable weak layer of surface hoar that is down 40-100 cm and human triggering remains possible. Treat this layer with caution and choose relatively conservative terrain.
No new activity was reported on Monday or Tuesday.
On Sunday, there were reports of numerous natural and explosives triggered avalanches up to size 2.5
On Saturday, there were a few reports of natural and human triggered avalanches up to size 2. Check out this MIN report detailing the touchy conditions found in the Allan Creek area on Saturday.
On Friday, there were a few reports of natural and human triggered avalanches. Check out this great MIN report from Allan Creek that outlines reactive storm slab conditions. Here is another great MIN report about similar conditions further north in the region.
Snowpack Summary
The Cariboos have seen up to 70 cm of new snow over the past week.
40-100 cm of snow is now sitting on a widespread layer of feathery surface hoar crystals. There is some uncertainty as to how much strength this interface has gained over the last few days and it should be treated with caution.
A weak layer formed in late November is now buried around 1 m or more below the surface. This interface may present as surface hoar, a crust, facets or a combination, depending on elevation and aspect.
Terrain and Travel
- Use conservative route selection. Choose simple, low-angle, well-supported terrain with no overhead hazard.
- Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.
- Caution around convexities or sharp changes in terrain.
- Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
- Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
Problems
Persistent Slabs
All of the old storm snow is slowly settling into a slab which rests on weak surface hoar 40 to 100 cm below the surface. Natural avalanche activity has waned, but human triggering remains possible, especially in more challenging/complex terrain. This isn't the kind of avalanche problem you can feel under your skis, track or feet, it's far too deep for that. The only way to manage a problem like this is to choose well supported terrain free of overhead hazard.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Wind Slabs
Winds out of the south/southwest may begin to form wind slabs in lee alpine features Thursday afternoon.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Dec 26th, 2019 5:00PM
