Avalanche Forecast

Issued: Jan 6th, 2021 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

The stormy weather may be over, but the snowpack is complex. Resist the urge to venture into bigger terrain until the snowpack has had a chance to gain some strength. The best riding is likely to be found on low angle slopes in wind sheltered areas.

Summary

Confidence

Moderate - Uncertainty is due to the fact that persistent slabs are particularly difficult to forecast.

Weather Forecast

WEDNESDAY NIGHT - Mainly cloudy / light west wind / alpine low temperature near -7 

THURSDAY - A mix of sun and cloud/ light northwest wind / alpine high temperature near -4 

FRIDAY - A mix of sun and cloud / light to moderate southeast wind / alpine high temperature near -3 

SATURDAY - A mix of sun and cloud / light west wind / alpine high temperature near -8

Avalanche Summary

On Tuesday, there was a human triggered size 2.5 avalanche reported on an east aspect at treeline in the Lower Holt area, near Golden. Two people were caught in this avalanche but were luckily uninjured. For a full report of this incident, click here.

There was another human triggered avalanche reported in the region on Tuesday on a northeast aspect at treeline near Glacier National Park. The MIN report can be viewed here.

There were a few reports of natural and explosives triggered size 2-2.5 wind and storm slab avalanches on Monday.

On Sunday there were reports of numerous natural, human and explosives triggered avalanches up to size 2. There was also one natural size 2.5 deep persistent slab avalanche reported on a north aspect at 2500 m near Invermere. 

A notable MIN from Sunday can be viewed Here.

Last Thursday, a ski cut resulted in a size 2 persistent slab avalanche on a northeast aspect in the alpine near Kicking Horse Mountain Resort. MIN report HERE.

These recent avalanches are a reminder that when persistent slabs are the problem, conservative terrain choices are the answer.

Snowpack Summary

Recent fresh snow with strong southerly wind has likely formed wind slabs in leeward terrain features at upper elevations.

There are currently several layers of concern in much of the region's snowpack. 40-60 cm of snow sits on a weak layer of surface hoar that was reported in the Golden area. 

The mid-December surface hoar is now down 90-140 cm. Although there have been no new reports of avalanches on this layer in the last few days, it remains possible to trigger where it is well preserved. There may also be a crust near, or instead of this layer in some areas.

The lower snowpack is characterized by more crusts, the most notable is a rain crust from early November that is sitting near the base of the snowpack, surrounded by a weak layer of sugary facets. It is most likely to be reactive to human triggers in steep, shallow, rocky areas with a thin to thick snowpack.

Terrain and Travel

  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Uncertainty is best managed through conservative terrain choices at this time.

Problems

Wind Slabs

An icon showing Wind Slabs

Recent fresh snow and strong southwest winds have likely formed wind slabs in lee terrain. 

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

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

A weak layer of surface hoar down 50-100 cm has been reactive to human triggers in the past week. 

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A crust buried near the bottom of the snowpack has been responsible for a few large avalanches in the past week.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2.5 - 4

Valid until: Jan 7th, 2021 4:00PM