Avalanche Forecast
Issued: Jan 25th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs.
bchristie,
Avalanche Canada
Sheltered, shady terrain may still hold soft snow that doesn't sit on top of a crust. Avoid shallow rocky start zones where you could trigger a deep persistent slab.
Summary
Confidence
Weather Forecast
Tuesday Night: Mostly cloudy. No new snow expected. Moderate southwest wind trending to strong northwest at higher elevations. Freezing levels fall to near valley bottom. Alpine low around -7 C.
Wednesday: Mostly cloudy, localized clearing. Possible trace of snow expected. Light southwest wind, trending to strong northwest at higher elevations. Freezing levels drop to valley bottom overnight, rise back to 750 m by the afternoon. Alpine high around -7 C.
Thursday: Mostly sunny. No new snow expected. Light southwest wind trending to strong northwest at higher elevations. Freezing level at valley bottom overnight, rising to 750 m by the afternoon.
Friday: Mostly sunny. No new snow expected. Moderate southwest wind trending to extreme west at higher elevations. Freezing level at valley bottom overnight, rising to 1000 m by the afternoon.
Avalanche Summary
On Tuesday, neighbouring Waterton National Park reported a few small to large natural windslab avalanches from steep, alpine features, and a couple of small, rider triggered windslab avalanches on reverse loaded, steep rolls.
No new avalanches were reported on Sunday or Monday.
On Saturday, avalanche control with explosives produced a couple of small windslab avalanches around treeline. Also, neighbouring Waterton National Park reported a few natural windslab avalanches to size 2 on solar aspects in the alpine.
Snowpack Summary
Surface hoar up to 15 mm has been reported in areas around Fernie. A Mountain Information Network post also reports surface hoar in the Corbin area. See here for more details. Patchy sun crust may exist on steep, solar aspects.
The upper snowpack consists of windslabs 20-60 cm deep in exposed terrain, and 15-20 cm of settling storm snow from last week.
Around 2200 m and below, these windslabs overlie a crust buried on January 18th, which caps a dense 15 to 30 cm of settled snow. On some windward slopes, the wind has scoured the surface back down to this crust. The crust varies with aspect and elevation from thin (2 cm thick) in the alpine to (4 cm) thick below treeline.
The midpack is strong and well consolidated above the early December crust/ facet interface.
The most notable layer of concern in the snowpack is a widespread crust that was formed in early December and is now down 100-270 cm. With warming last week this deep persistent slab problem woke up and produced several very large avalanches. Daytime warming, solar radiation, smaller avalanches, and cornice fall could continue to play a role in triggering deep persistent slabs.
Terrain and Travel
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Avoid terrain traps where the consequence of any avalanche could be serious.
Problems
Deep Persistent Slabs
The early December crust can be found 100-270 cm deep.
Thin rocky start zones are the most likely place to trigger this layer. Also, daytime warming, solar radiation, cornice fall, and step-downs from smaller avalanches could increase the chance of an avalanche on this layer.
This deep persistent slab problem has been less active recently, but we have been reminded multiple times in the last month that this layer could remain a concern all winter.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 26th, 2022 4:00PM
