Avalanche Forecast
Issued: Jan 30th, 2017 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Wind Slabs.
tim haggarty,
Avalanche Canada
Ice climbers: be wary of recent loading that may not be evident at the valley bottom levels. Several events over the weekend originating at upper elevations affected the climbs at lower levels.
Summary
Weather Forecast
The jet stream that has been directly over our heads for the last few days will shift further south tonight. Cold northern air will return with north winds at upper elevations and plunging temperatures pushing away some remaining cloud and moisture. Clear, Calm and Cold by Wednesday night. This state of affairs looks to last until Friday.
Snowpack Summary
In many areas, a generally weak snowpack exists below 2000-2200m . At 2000m, there is generally 140 cm of snow, with the Jan 17 surface hoar layer down 30cm producing sudden planar test results. In the mid-pack, the Dec facets are 20cm thick, and near the ground some weak facets sit just below on an old ice crust.
Avalanche Summary
Strong to Extreme South and West winds have produced an avalanche cycle over the weekend that continued today. Sunday, natural avalanches could originating higher on Mts Stephen, Dennis and Field spilled over ice climbs at the valley bottom level. Fresh windslabs as well as avalanches involving deeper layers have been observed in the BYK region.
Confidence
Problems
Persistent Slabs
The generally weak, facetted mid pack is producing moderate to hard shears. In the upper snowpack around treeline a buried layer of surface hoar produces variable shears. Increased slab development overlying these layers is likely with recent winds.
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Wind Slabs
Fresh windslabs exist in the immediate lees and will remain reactive for some time after the winds abate.
- Use caution in lee areas. Recent wind loading have created wind slabs.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: North, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 31st, 2017 4:00PM
