Avalanche Forecast

Issued: Dec 16th, 2019 4:00PM

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

Parks Canada aaron beardmore, Parks Canada

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Increased wind and small amounts of new snow are creating new reactive wind-slabs at ridge top.

Summary

Weather Forecast

Seasonal temps (-5 in the valley, -10 at the ridge) for the next few days. Light snow is expected totalling 10cm by Thursday midday. Ridgetop wind is expected to be in the strong to extreme range from the W-SW on Tuesday afternoon. Some more significant snow is expected on the weekend, but the outlook is still uncertain.

Snowpack Summary

New windslabs are being created by increased west wind. Beneath the recent 40-60cm of storm snow, the snowpack structure is generally weak, consisting of facets and depth hoar. The Nov crust is present up to 2500m and ~30 cm up from ground. In areas with a deeper snowpack (Tak Falls, Stanley Mitchell, etc.) the basal weakness is less pronounced.

Avalanche Summary

Small windslabs (size 1) were reported near Mt Ogden today. They likely occurred within the last 24 hours. Additionally, a small wind slab was triggered by 2 ice climbers on the half way ledge on Bourgeau Left today.

Confidence

Wind speed and direction is uncertain on Tuesday

Problems

Wind Slabs

An icon showing Wind Slabs

Overnight wind transport has created thin wind slabs predominantly on East aspects directly below ridge top. Pay attention to wind values and new snow amounts that contribute to this problem over the next 24 hours.

  • Caution on open steep slopes at treeline that have been exposed to wind loading.
  • Use caution in lee areas. Recent wind loading has created slabs over weaker snow.

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

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 1.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The recent snow sits over weak facet and crust layers. As time goes on the chance of triggering is becoming less likely, but there is lots of uncertainty as to where you could trigger an avalanche and what it will take to get it moving.

  • Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Valid until: Dec 17th, 2019 4:00PM