Avalanche Forecast

Issued: Jan 5th, 2019 3:00PM

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

Alberta Parks mike.koppang, Alberta Parks

Natural activity is decreasing but human triggering is a very real possibility.  Stick to conservative terrain for a few days and let the snowpack adjust to the new load.

Summary

Confidence

High -

Weather Forecast

Sunday may see a few cm of new snow overnight with temperatures cooling slights and winds becoming more moderate out of the SW.

Avalanche Summary

Several natural avalanches were observed up to sz 3 mainly on N and E aspects in alpine areas. These slabs were up to 1m deep and 300m wide running to the top of their normal runouts. The majority of the avalanche activity looks to have occurred mid storm. A few smaller slabs were observed in thin treeline snowpack areas failing at ground but running far due to the widespread faceted base.

Snowpack Summary

The storm snow (40-50cm) that we received over the past few days is beginning to settle and SLOWLY strengthen. Shears with the upper snowpack and at the storm snow interface have tightened up but we still have a big concern for the weak facetted base that persists everywhere. New winds slabs should be expected in open wind affected areas in the alpine especially on N and E aspects. Moderate sudden collapse failures within the basal facets indicate the snowpack is still ripe for human triggering. Give the snowpack time to strengthen and stick to mellow low consequence terrain.

Problems

Wind Slabs

An icon showing Wind Slabs
Lots of recent snow is available for transport and winds are forecast to increase on Sunday.  Watch for windslabs growing and becoming more reactive throughout the day.
Avoid convexities or areas with a thin or variable snowpack.Avoid freshly wind loaded features.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The new snow load had not improved this layer. It is as delicate as ever. Do not underestimate its avalanche potential!  Avoid thin spaces.
Remote triggering is a concern, watch out for adjacent slopes.Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 3

Valid until: Jan 6th, 2019 2:00PM