Archived

Avalanche Forecast

Mar 30th, 2017–Apr 2nd, 2017

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

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: Waterton Lakes.

Snowfall amounts for Friday are uncertain, exercise extra caution if forecast accumulations are exceeded.

Weather Forecast

Friday: Snowfall (10-15cm) in the AM (clearing trend in the PM). Ridgetop wind moderate N (trending light). Treeline temps, High -2, Low -6.Saturday: Partly cloudy, PM flurries. Ridgetop wind strong SW. Treeline temps, High -1, Low -4.Sunday: Parlty cloudy, AM flurries. Ridgetop wind mod-strong SW. Treeline temps, High -7, Low -10.

Snowpack Summary

Fresh storm slabs will form Friday with incoming snow and N winds. These will likely be touchy as they will overlie; a thin melt-freeze crust on all but north aspects above 2000m, scoured old crust in wind exposed terrain, and wind slab 10-40cm deep on N aspects.Â Treeline and above, the basal snowpack remains faceted and weak in many locations.

Avalanche Summary

A few small-large (up to size 2.0) wind slabs were observed on alpine N aspects Thursday. Several large to very large avalanches from last week and the week before suggest that deep persistent weaknesses in the snowpack will remain as a concern well in to the spring.

Confidence

Forecast snowfall amounts are uncertain

Avalanche Problems

Wind Slabs

Wind slabs formed by SW winds on Thursday will be difficult to detect under Fridays new snow. Fresh wind slabs will likely form with SW winds forecast for the weekend.

Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 2

Storm Slabs

Keep an eye out for reverse loading created by an upslope storm.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

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

Elevations: All elevations.

Likelihood: Likely - Very Likely

Expected Size: 1 - 2

Deep Persistent Slabs

Facets in the bottom 1/3rd of the snowpack are persisting as a weak layer to be respected. These could be triggered by large triggers such as cornice falls and wind slab avalanches.

Pay attention to overhead hazards like cornices which could trigger the deep persistent slab.Be wary of large alpine slopes that did not previously avalanche.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Unlikely

Expected Size: 2 - 4