North Rockies

Date Issued: Saturday, November 27, 2021, 04:00
Valid Until: Sunday, November 28, 2021, 04:00
Prepared by: bchristie

This is an archived avalanche bulletin.

The break from storms may not be long enough to explore new terrain. Watch for new reactive slabs as the next wave arrives this afternoon.

Danger ratings

Saturday
Alpine
3 - Considerable
Treeline
3 - Considerable
Below Treeline
2 - Moderate

Travel and Terrain Advice

    Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
    Avoid freshly wind loaded terrain features.
	
    Remember that the snowpack will be significantly different at higher elevations than lower down.
    Don't be too cavalier with decision making, storm slabs may remain sensitive to human triggering.
	
Avalanche Problem 1: Storm Slab
What Elevation? belowTreeline, Treeline, Alpine
Which Slopes? North, Northeast, East, Southeast, south, Southwest, West, Northwest
Chances of Avalanches? Likely
Expected Size? Small - Large

Slabs built during the storm may still be reactive. Travelling through snow that remains wet and heavy at lower elevations may produce small loose wet avalanches. Avalanches have the potential to be larger in areas like Pine Pass that saw more snow during the storm. 

Avalanche Summary

There is evidence that an avalanche cycle occurred in the north of the region during the storm. Avalanches ranged from size 1 to size 2.5, with the majority starting around treeline.

If you are getting out in the mountains, we strongly encourage people to share observations on the Mountain Information Network.
Snowpack Summary

Storm slabs from the recent snowfall are settling, but remain sensitive to human triggers.

The new snow and total snowpack are significantly deeper in the Pine Pass area than the rest of the region. Strong southwesterly winds and warm temperatures have made conditions quite variable depending on elevation and wind exposure.

Recent observations suggest treeline snow depths are around 80-140 cm with very little snow below 1400 m in much of the region except for the Pine Pass area which now has enough snow below treeline to avalanche.

A series of storms over the past few weeks delivered about 40-80 cm of snow, which sits above an early season crust(s). Reports indicate the snow has generally bonded well to the early season crusts. Exceptions may be shallow alpine slopes along the eastern side of the Rockies towards Jasper.

Weather Summary

The see-saw weather cycle continues. Clearer, colder, and calmer weather will shift to wet, warm, and windy this afternoon, and we'll do it all again next week.

FRIDAY NIGHT: Overcast. Freezing level falls to valley bottom. Strong southwest wind. No precipitation expected.

SATURDAY: Broken cloud cover with possible sunny periods. Freezing level starts at valley bottom and rises to 1500 m through the day. Alpine low -10. Moderate to strong southwest wind. 5-10 cm snow expected.

Confidence
    Low
    Uncertainty is due to the limited number of field observations.