Avalanche Forecast

Issued: Mar 9th, 2020 5:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Storm slabs may be reactive to human triggering, especially in wind loaded areas at upper elevations. Watch for signs of instability such as whumphing, cracking and recent avalanches.

Summary

Confidence

Moderate -

Weather Forecast

MONDAY NIGHT - Cloudy with clear periods / west wind, 20-40 km/h / alpine low temperature near -11

TUESDAY- Mainly cloudy with isolated flurries / southwest wind, 40-60 km/h / alpine high temperature near -7

WEDNESDAY - A mix of sun and cloud with isolated flurries / northwest wind, 20-40 km/h / alpine high temperature near -6

THURSDAY- A mix of sun and cloud / west wind, 20-30 km/h / alpine high temperature near -8

Avalanche Summary

In the neighbouring Waterton Lakes National Park region, there were several natural loose dry avalanches up to size 1.5 reported on Monday.

In the neighbouring Lizard Range on Sunday, loose dry and soft slab avalanches were sensitive to human triggering and explosive avalanche control work to size 1.5. These avalanches were 10 to 20 cm in depth, running fast and far. 

Snowpack Summary

20 to 30 cm of recent storm snow sits on wind slabs in exposed areas, and a sun crust on solar aspects (south through west facing slopes). Melt-freeze crusts extend up to about 1900 m on other aspects. 

A thick crust with facets on it currently sits 40-80 cm below the surface and can be found up to 2100 m. The middle of the snowpack is generally strong, but the base of the snowpack contains basal facets that are most prominent in shallow rocky start zones.

Terrain and Travel

  • Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.

Problems

Storm Slabs

An icon showing Storm Slabs

20-30 cm of new snow has formed storm slabs that may not be bonding well with the previous snow surface. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Weak snow at the bottom of the snowpack hasn't gone away. Evidence of deep persistent slab avalanches has been focused in the Sparwood-Elkford area over the past month. Human triggering is most likely around steep rocky terrain features, or anywhere the snowpack is thin and weak. Cornices have grown large and loom over many ridge lines, a failing cornice could initiate a deep persistent slab when it impacts the slope below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2.5 - 3.5

Valid until: Mar 10th, 2020 4:00PM

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