Register
Get forecast notifications
Create an account to receive email notifications when forecasts are published.
Login
Archived

Avalanche Forecast

Nov 19th, 2020–Nov 20th, 2020
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

New snow, wind, and a weak layer of crust and facets are making the snowpack more complex. Time to dial back terrain choices. Good ski conditions in sheltered areas that are deep enough to cover the rocks! SH

Weather Forecast

5-10cm expected on Friday, with increasing winds at upper elevations to strong from the S/SW. Temperatures -10 in the valley warming to -5C, and -12 to -15C in the alpine.

Snowpack Summary

15-30 cm snow over the last few days with new and buried windslabs existing in alpine and treeline. The Nov. 5 Facets/crust combo is 20-40 cm off the ground and is buried 40-70cm producing variable test results. It extends up to 2400m on shady aspects and higher on solar aspects. Total snow depths at treeline are 50-100 cm.

Avalanche Summary

Avalanche control on 93S yesterday produced a few slides up to size 2. Lake Louise ski patrol were able to trigger a size 2 wind slab in N facing terrain that hadn't had previous control. Skier remote report sz 1.5 today on facets to ground (40cm deep) at 2000m, 80m wide near Watermelon peak. Other audible avalanches heard but poor visibility.

Confidence

Due to the number and quality of field observations

Avalanche Problems

Wind Slabs

Wind slabs are forming at treeline and alpine elevations from recent storm snow and increased winds. Whumpfing noted Thursday and ski hills reporting explosive triggered slabs. Expect these to continue growing with increased winds Friday.

  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2

Deep Persistent Slabs

The Nov.5 crust/ facet layer exists up to 2500m on shady aspects, and higher on solar aspects. Where there is a dense slab overlying this layer, it is starting to become reactive to skier traffic. This will be a layer of concern for a long time.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Loose Dry

Up to 30cm over the past few days which will be prone to sluffing in steep terrain, especially for climbers and steep gully skiers. This will be less of a problem in areas that don't receive as much snow.

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 1.5