Avalanche Forecast
Issued: Feb 17th, 2012 9:48AM
The alpine rating is Wind Slabs, Deep Persistent Slabs and Cornices.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Fair - Intensity of incoming weather is uncertain on Saturday
Weather Forecast
By the end of Saturday, western parts of the region could see up to 15 cm of low density new snow as a frontal system tracks along the US/Canadian border. Eastern parts will see more in the region of 5 cm. Moderate southwest winds are expected and alpine temperatures should hover between -5 and -10C. For Sunday and Monday, a series of weak disturbances embedded in a northwesterly flow will bring flurries or very light precipitation. Winds should be generally light or moderate, with the switch from southwesterly to northwesterly expected to occur on Sunday night.
Avalanche Summary
No recent avalanches have been reported from this region. Deep persistent slab avalanches remain possible in isolated terrain features; i.e. heavy triggers in shallow rocky snowpack areas on unsupported slopes. Check out the Avalanche Image Gallery under the Library tab for some photos of last weekends deep persistent slab avalanche cycle.
Snowpack Summary
"Dust on a crust" on southerly aspects, where recent sunshine formed a crust that has since been buried by light snow. Shady slopes do not have this crust. Cool alpine temperatures are promoting facet growth in the upper snowpack keeping the surface snow fairly soft. Just a few cm of recent snow now sits on a variable weak layer comprising surface hoar (most likely in the west of the region), sugary facets on shady N'ly and sun crusts on solar aspects. These interfaces need watching as they receive more snow load and/or wind slab builds on top of these surfaces. Below that, approximately 20 cm of near-surface facets can be found on shady slopes. While the mid-pack is quite strong in most locations, basal facets remain a concern on shady alpine slopes that did not avalanche in the last cycle. Data that supports this lingering concern includes recent professional observations that found easy to moderate compression test results with a sudden "drop" fracture down 80 and 100 cm in a location with a 160 cm snowpack.
Problems
Wind Slabs
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Deep Persistent Slabs
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Feb 18th, 2012 9:00AM