Avalanche Forecast

Issued: Dec 22nd, 2013 4:00PM

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

Avalanche Canada conrad janzen, Avalanche Canada

A weak, early season snowpack dominates the forecast area, and will for the foreseeable future. Triggering full depth avalanches is a real possibility. Stick to well supported lower angle terrain and enjoy the recent snow! CJ

Summary

Weather Forecast

Snowfall amounts of 5-10cm are forecast for Sunday night and into Monday accompanied by gusty West winds. Depending on amounts this may increase the avalanche hazard slightly especially in the alpine. Continued flurries and gusty W winds are forecast through Wednesday with alpine temperatures ranging between -7'C and -15'C.

Snowpack Summary

20-30cm of recent snow now sits on top of a generally weak snowpack. Some new wind slabs are present near ridge crests in alpine areas.  The lower half of the snowpack is comprised of weak facets and depth hoar. Total snowpack depths range from 60-100 cm, with the deeper snow located on the western side of the forecast region.

Avalanche Summary

Several natural slab avalanches up to size 3 were reported in alpine terrain in Banff and Jasper over the past 36hrs.  All of these were failing on the weak basal facets layers near the ground. A skier remote size 1.5 was also reported yesterday on a small steep N facing tree line feature at Bow Summit. 

Confidence

Forecast snowfall amounts are uncertain on Monday

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The snowpack is weak and should not be trusted. This is classic early season Rocky Mountain conditions, and it is not expected to change in the near future. Settle in to this reality, and stick to mellow terrain over the next while.

  • Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.
  • Avoid steep, open slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Wind Slabs

An icon showing Wind Slabs

Watch for new wind slabs forming in open areas above tree line as well as old wind slabs which may be hidden beneath the recent snow. Check leeward or cross loaded areas carefully for the presence of wind slabs before entering these types of lines.

  • The recent snow may now be hiding windslabs that were easily visible before the snow fell.
  • Use caution in lee areas in the alpine. 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

Valid until: Dec 23rd, 2013 4:00PM