Avalanche Forecast

Issued: Jan 17th, 2023 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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**UPDATED 6:40 AM** New snow and wind have created dangerous avalanche conditions around Pine Pass.

Summary

Confidence

Moderate

Avalanche Summary

No new avalanches were reported on Sunday or Monday. On Saturday, a large (size 2) avalanche was observed at Hassler. It was potentially remotely triggered by a snowmobiler, and propagated widely across a sparsely treed slope. Several natural storm slab and wet loose avalanches occurred during the stormy weather on Friday.

Although there has been a decline in observed avalanche activity, triggering a large persistent slab avalanche remains possible and terrain should be chosen with care.

Snowpack Summary

New snow is gradually accumulating above settled snow from last week's warm storm. At lower elevations, a rain crust exists near the surface, with reported elevations extending up roughly 1200 m.

Snowpack depths are shallower than normal, and several buried weak layers have been a concern over the past few weeks. One is a recently buried surface hoar layer found 20 to 40 cm deep in sheltered terrain features at treeline and above. At this same depth, a crust exists on steep south facing slopes. Another layer of facets, crust, and surface hoar was buried around Christmas and is now 40 to 70 cm deep. Finally, a layer of large, weak facets buried in November is found near the bottom of the snowpack. This layer is likely most problematic in alpine terrain, where shallower avalanches could scrub down to these basal facets.

Recent observations suggest the buried weak layers are gaining strength, but not enough to trust them in high consequence terrain.

Weather Summary

Tuesday night

Cloudy with periods of snow, 10 to 20 cm, 60 km/h southwest wind, treeline temperatures around -5 °C with freezing level around 1000 m.

Wednesday

Cloudy with scattered flurries bringing 1 to 5 cm of snow, 50 km/h southwest wind, freezing level around 1000 m with treeline temperatures around -4 °C.

Thursday

Cold front passes in the early morning with 5 to 10 cm of new snow then some sunny breaks in the afternoon, 30 to 50 km/h west wind, freezing level drops to valley bottom with treeline temperatures drop to -8 °C.

Friday

Mostly cloudy, scattered flurries with 1 to 5 cm of snow, 40 to 60 km/h southwest wind, freezing level climbing to 1200 m with treeline temperatures warming to -3 °C.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Be carefull around freshly wind loaded features.
  • Dial back your terrain choices if you are seeing more than 20 cm of new snow.
  • Use conservative route selection and resist venturing out into complex terrain.
  • Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
  • Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.

Problems

Storm Slabs

An icon showing Storm Slabs

New snow and wind is forming unstable storm slabs on steep terrain features.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

Several buried weak layers remain a concern for human triggering. At treeline elevations, the main concern is surface hoar and crust layers in the middle of the snowpack, especially on steep convex openings. In the alpine, the main concern is weak facets at the bottom of the snowpack, especially on rocky slopes with variable snow depths.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Valid until: Jan 18th, 2023 4:00PM