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North Rockies Avalanche Forecast - March 22, 2021

Recently formed slabs may remain triggerable by riders on Tuesday. New slabs will likely rapidly form during Wednesday's storm.
North Rockies Avalanche

Recently formed slabs may remain triggerable by riders on Tuesday. New slabs will likely rapidly form during Wednesday's storm.

Tuesday

Alpine - Considerable
Treeline - Moderate
Below treeline - Low

Wednesday

Alpine - High
Treeline - Considerable
Below treeline - Moderate

Thursday

Alpine - Considerable
Treeline - Moderate
Below treeline - Low

Avalanche Summary

The recent snow was reported as being reactive to rider traffic over the weekend, particularly in steep wind-affected terrain. Looking forward, storm and wind slabs could continue to be triggered by riders as the wind speed remains elevated. New slabs are likely to develop on Wednesday.

Snowpack Summary

Around 20 to 30 cm of snow accumulated over the weekend for most riding areas. Southwest wind has likely formed wind slabs up high, as the snow is blown around at treeline and alpine elevations. The snow may also have settled into storm slabs, particularly in steep terrain sheltered from the wind. This snow overlies a hard melt-freeze crust up to treeline and to mountain tops on sun-exposed slopes. Another 20 to 40 cm of snow may accumulated by Wednesday afternoon, forming new storm and wind slabs. Cornices are very large along ridgelines and always have the possibility of failing naturally or from the weight of a human.

A weak layer of facets buried mid-February may be found around 100 to 120 cm deep, or shallower in the east of the region and in thin snowpack areas. The most likely place to trigger this layer is where the snowpack is shallow in alpine terrain. Large loads, such a cornice falls or multiple sleds on the same slope, often trigger slopes that single rider couldn't trigger.

Weather Forecast

TUESDAY: Cloudy with snowfall, accumulation 5 to 10 cm, 30 km/h west wind, alpine temperature -8 C.

WEDNESDAY: Cloudy with snowfall, accumulation 20 to 40 cm, 50 km/h northwest wind, alpine temperature -5 C.

THURSDAY: Partly cloudy, 20 km/h northwest wind, alpine temperature -7 C.

Travel and Terrain Advice

  • Watch for changing conditions today, storm slabs may become increasingly reactive.
  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid exposure to slopes that have cornices overhead.
  • Be aware of the potential for large avalanches due to the presence of a persistent slab.
  • Avoid areas with a thin or variable snowpack.