Avalog Join
Archived

Avalanche Forecast

Nov 18th, 2011–Nov 19th, 2011
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
1: Low
The avalanche danger rating below treeline will be low

Regions: Purcells.

This bulletin is based on limited data. Local variation in conditions and danger levels are likely to exist. To produce more accurate forecasts, we need information. Please send an email to forecaster@avalanche.ca

Confidence

Poor - Due to limited field observations

Weather Forecast

The ridge of high pressure has moved over the interior mountains and has brought cooler temperatures and drier conditions. Saturday is forecast to be mostly sunny and cold (-20.0 c) above treeline. Sunday should continue to be cold and mostly clear. The next storm is forecast to move in from the coast late Monday or overnight into Tuesday.

Avalanche Summary

A cycle of natural avalanche activity was observed in Quartz Creek on Sunday. Wind slabs (20cm deep) and persistent slabs (60cm deep) were observed. Persistent slabs were propagating widely and running on a weakness towards the base of the snowpack. Observations are limited to the northern Purcells so I don't know if this kind of thing is still occurring here.

Snowpack Summary

There is significant variability in the snowpack across the region. Snowpack depth at treeline varies from around 40-130cm. Up to 50cm of snow fell late last week and over the weekend, which was redistributed by strong winds blowing first from the south and then from the north-west. A basal layer of facets was reported in the Dogtooth Range, with a weak interface between the lower facets and recent storm snow. Observations are limited. New snow and wind are in the forecast although not as much as in the Columbias to the west. Some new windslab formation is possible.

Avalanche Problems

Wind Slabs

Strong southerly, then north-westerly, winds have shifted snow onto downwind slopes.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Persistent Slabs

Over the weekend, widespread storm slab activity was observed. Weak snow at the base of the snowpack will take time to gain strength. Steep or exposed terrain should be treated with suspicion. No new info so will keep this problem in for now.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 3