Avalanche Forecast

Issued: Nov 18th, 2020 4:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is low. Known problems include Wind Slabs and Loose Dry.

Aaron Beardmore,

Be alert in areas that harbor wind slabs. More snow and wind input is expected over the next two days.

Summary

Weather Forecast

Incoming snow will start on Thurs and deliver approximately 20cm to the forecast region by midday on Friday. The temperature will drop bringing sub zero values to the valley level again. The wind will increase and stay elevated throughout Thurs and Fri in the strong range from the SW.

Snowpack Summary

40-60 cm of settled snow overlies the Nov 5th crust with the higher amounts around Sunshine. Windslabs exist in alpine and at treeline. The crust is 1-10 cm thick and generally thickest around Sunshine. It extends up to 2400m on polar aspects and slightly higher around Sunshine and on solar aspects. Total snow depths at treeline are 50-100 cm.

Avalanche Summary

Avalanche control on 93S today produced a few slides up to size 2. Evidence of a previous natural cycle (last 36 hours) was evident up to size 2. Sunshine and Lake Louise ski patrol were able to trigger small windslabs with explosives today and most notably a Sunshine ski patroller ski cut a size 2 wind slab.

Confidence

Due to the number of field observations on Wednesday

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs exist in the alpine and at treeline and more forecasted wind and snow will create new ones on Thursday. Today wind-slabs were triggered with explosives and ran on the Nov 5 crust, approx 50cm down.

  • Use caution in lee areas. Recent wind loading have created wind slabs.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Loose Dry

An icon showing Loose Dry

With up to 20 cm forecasted Thurs/Fri, watch for sluffing in steep terrain. This will be less of a problem in areas that don't receive as much snow.

  • Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.
  • Use caution above cliffs where small avalanches may have severe consequences.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Nov 19th, 2020 4:00PM