Banff Yoho & Kootenay National Park Avalanche Forecast

Issued: Mar 1st, 2021 5:14PM

Mon Mar 1st Current Conditions
Alpine Considerable Treeline Moderate Below Treeline Moderate
Tue Mar 2nd 2 Day Outlook
Alpine Considerable Treeline Moderate Below Treeline Moderate
Wed Mar 3rd 3 Day Outlook
Alpine Moderate Treeline Moderate Below Treeline Moderate

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

We have raised the BTL rating to Moderate, mostly for the Kootenay region where a number of close calls have occurred in the past few days. This one looks serious. The pattern is: South aspect, TL & BTL,, buried crust and facets with an 80 cm slab.

Summary

Weather Forecast

The westerly flow continues and will bring another 5 cm on Monday night with clearing by mid-day Tuesday. Expect the alpine winds to remain strong out of the west, also calming down on Tuesday afternoon. Wednesday and Thursday look beautiful; blue sky and warm.  Watch out for the sun's effects to the snowpack on Wednesday.

Snowpack Summary

Strong SW winds for the past 36-hours has blown the recent storm snow into windslabs in alpine lee areas and exposed tree line slopes. In Kootenay and around Lake Louise we are tracking a persistent layer of suncrust and facets down 30-60 cm that is producing avalanches and test results. Heads up, this layer is isolated but reacts to skiers.

Avalanche Summary

Two close calls in the Simpson area of Kootenay Park in the past 48-hours. South aspect at treeline and below treeline in the burnt forest is the pattern. With the huge increase in skier traffic in this area, do not lose sight of the fact that this is TIGER COUNTRY. Big slopes, steep runs, and common to get avalanches on buried crusts in March.

Confidence

Timing or intensity of solar radiation is uncertain on Wednesday

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely

Expected Size

1 - 2.5

36-hours of moderate to strong winds from the SW have blown the recent storm snow into windslabs in open areas. These could be quite deep in immediate lee areas. Check this on small slopes with no consequence and extrapolate to the bigger terrain.

  • Watch for shooting cracks or stiffer feeling snow. Avoid areas that appear wind loaded.
  • Use caution in lee areas. Recent wind loading has created slabs over weaker snow.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Persistent Slabs

An icon showing Persistent Slabs

Likelihood

Possible - Unlikely

Expected Size

1.5 - 3

Two weak facet interfaces exist in the top meter of the snowpack. On south aspects this problem could be associated with a sun crust. These layers are present in many areas, but we have uncertainty on where they will be reactive.

  • Dig down to find and test weak layers before committing to a line.

Aspects:

All aspects.

Elevations:

All elevations.

Valid until: Mar 2nd, 2021 4:00PM

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.