Avalanche Forecast
Issued: Jan 12th, 2018 4:25PM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Moderate -
Weather Forecast
Saturday: Overcast with possible sunny breaks in the afternoon / Light and variable winds / Freezing level rising to 1500mSunday: Clear skies / Light and variable winds / Temperature inversion with valley temperatures remaining well below freezing and alpine temperatures reaching 2 degreesMonday: Clear skies / Light and variable winds / Temperature inversion with valley temperatures remaining well below freezing and alpine temperatures reaching 2 degrees
Avalanche Summary
On Wednesday control work around Kootenay Pass produced avalanches to size 3.5 on a variety of aspects. On the same day, natural avalanches failed to size 2.5. These avalanches may have started as storm slabs failing on the January 5th surface hoar, but stepped down to the mid-December and/or late November weak layers. An awesome MIN post from the same day also details some spooky skier-triggered avalanche activity around treeline in the Nelson area. Click here for details. On Thursday, a skier remotely triggered a size 1.5 slab avalanche from a distance of 50 metres in the mountains north of Nelson. This avalanche, which failed on the January 5 surface hoar, shows how touchy this interface continues to be. Explosives control in the Kootenay Pass area continued to trigger persistent slab avalanches up to size 2.5.At the time of publishing this bulletin, no reports were available from Friday.Looking forward, human triggering of large, destructive persistent slab avalanches at all elevation bands will remain a real possibility for the foreseeable future in many parts of the region. Warming and solar radiation on Sunday, will likely ignite another round of destructive natural activity
Snowpack Summary
40 to 80 cm of recent snow is settling into a cohesive slab on top of the reactive January 5th interface which consists of a crust/surface hoar combination on steep southerly aspects and pure surface hoar on remaining aspects. The late December surface hoar also remains reactive and is now down 50 to 95 cm below the surface. Adding to the complexity of the mid to upper snowpack is the mid-December surface hoar which is now 60 to 130 cm below the surface. This spooky interface continues to produce sudden snowpack test results and is most pronounced at treeline, but is also present below treeline. The overlying slab is now deep, dense and destructive. Two laminated crusts created by rain events in late November lay just below the mid-December interface, and may co-exist with facets. In shallow, rocky terrain the mid-December surface hoar and the late November crust seem to be reacting together which is a volatile combination.
Problems
Storm Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 13th, 2018 2:00PM