Parks Canada Jasper Snow Safety, Parks Canada

Jasper National Park Avalanche Forecast

Jan 10th, 2020 4:00PM

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

Natural activity is tapering off but human triggered avalanches initiating in the basal weakness remains likely in the right spot. Conservative line choice and mitigating overhead exposure is the key for safely venturing out before the deep freeze!

Summary

Weather Forecast

The arctic air mass continues to advance from the NE.

Saturday - Mainly cloudy with scattered flurries to 4 cm. Alp High -9 °C. Ridge wind SW10-25 km/h.

Sunday - Cloudy with sunny periods and isolated flurries. Ppt Trace. Alp Low -33 °C, High -18 °C. Wind SE10-20 km/h.

Visit CAA's Mountain Weather Forecast for more specific details.

Snowpack Summary

Up to 60cm new snow since January 1st. Consistent SW winds creating wind slab on lee aspects in the alpine and treeline. This overlies buried surface hoar up to 2000m in sheltered areas as well as buried wind slabs on lee features at treeline and above. Well consolidated midpack. The bottom of the snowpack consists of depth hoar and facets.

Avalanche Summary

Recent widespread avalanche cycle up to size 3 on all aspects and elevations - wind slab, dry loose and deep persistent slab.  Suspect continued slab development on lee features with natural activity tapering off.  Human triggering of wind slab and deep persistent remains likely.

Confidence

Due to the number and quality of field observations on Saturday

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely - Possible

Expected Size

1 - 3

Avalanche activity will taper off Saturday but human triggered avalanches are still likely.

  • Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.
  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects:

All aspects.

Elevations:

All elevations.

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Possible

Expected Size

1 - 3

On Wednesday numerous avalanches were observed throughout the region that failed to ground.

  • Use caution on open slopes and convex rolls
  • Be aware of thin areas that may propogate to deeper instabilites.

Aspects:

All aspects.

Elevations:

All elevations.

Loose Dry

An icon showing Loose Dry

Likelihood

Possible - Unlikely

Expected Size

1 - 2

Caution in steep gullies and terrain traps where a small sluff could have large consequences. Avoid terrain where this problem can initiate slab avalanches on deeper layers.

  • Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects:

All aspects.

Elevations:

All elevations.

Valid until: Jan 11th, 2020 4:00PM