Archived

Avalanche Forecast

Mar 28th, 2021–Mar 29th, 2021

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

2: Moderate

The avalanche danger rating below treeline will be moderate

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

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

Regions: Banff Yoho Kootenay.

Up to 35 cm of storm snow is expected accompanied by strong winds. Monday is a day to travel cautiously and investigate how the new snow is bonding to the previous surfaces. Choose more conservative terrain with low consequences to gather more info.

Weather Forecast

Another 10-20 cm of snow at treeline is forecast for most areas Sunday night with alpine winds dropping down to the moderate range and switching from SW to North. Treeline temperatures will fall to the -12 C to -18 C range overnight and stay cool on Monday. Some light flurries and light to moderate NW winds are expected on Monday.

Snowpack Summary

5 to 25 cm of snow at treeline on Sunday with the most in the 93N. New wind slabs in alpine and exposed treeline areas with strong to extreme S-SW winds. Moist snow below 1500 m. 20-50+ cm now sits over the March 19 interface of crust on solar aspects and facets on north aspects. Nov basal facets still prominent in shallow areas east of the divide.

Avalanche Summary

One natural size 2.5-3 came down the Mt Stephen path into the berm near Field. Small loose wet avalanches reported in the Field area below 1500 m. Some small wind slabs above treeline reported by local ski areas, and some sluffing in steep terrain reported on the 93N. Limited visibility in the alpine all day.

Confidence

Intensity of incoming weather systems is uncertain

Avalanche Problems

Wind Slabs

Widespread wind slab development in alpine and some exposed treeline areas is expected from strong to extreme SW winds and 10 to 35 cm of new snow. Use caution in any steep or loaded terrain until you have a sense for how reactive the new snow is.

Be careful with wind loaded pockets, especially in steep confined alpine terrain.
Use caution in lee areas. Recent wind loading have created wind slabs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Likely

Expected Size: 1 - 2.5

Loose Dry

The new snow will sluff easily in steep terrain, especially in areas that received the largest amounts over the past 24 hours.

On steep slopes, pull over periodically or cut into a new line to manage sluffing.
Be careful of loose dry power sluffing in steep, confined or exposed terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Likely

Expected Size: 1 - 1.5