Avalanche Forecast
Issued: Feb 4th, 2018 5:39PM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeSummary
Confidence
Low - Forecast snowfall amounts are uncertain on Monday
Weather Forecast
Sunday overnight into Monday: 10-15 cm snow Monday: Lingering flurries (5 - 10cm possible) / Light to moderate westerly winds / Freezing level around 1400mTuesday: Flurries (5-10 cm possible) / Moderate west winds / Freezing level around 1200mWednesday: 5-10cm of new snow / Moderate west winds / Freezing level near 1200mNote: Confidence is low for forecast wind values and precipitation amounts on Sunday overnight into Monday.
Avalanche Summary
On Sunday, ski cutting near Nelson produced many soft slab avalanches to size 1.5 on down wind (lee) features that had seen additional snow loading due to wind.Looking forward, expect newly formed storm slabs and the persistent slabs beneath them to remain reactive to human triggers with the potential for very large and destructive avalanches.
Snowpack Summary
Sunday afternoon saw heavy snowfall (15cm in 5 hours at Kootenay Pass) coupled with moderate to strong south west winds and rising avalanche danger. Elsewhere in the region, storm snow totals over the weekend were on the order of 15-30cm. Winds were gusting moderate at times and created fresh wind slabs on a wide range of aspects at upper elevations. Critical instabilities are buried well below the surface: See this video for a summary of conditions near Nelson. A mixture of weak surface hoar and/or a crust from mid-January is buried beneath all the storm snow at 90-120cm deep. Numerous recent avalanches to size 2.5 have been reported on this layer and large, destructive avalanches at this interface remain a concern.Below this layer lies a second crust/surface hoar interface buried early-January that is now 120-140 cm deep. Several recent avalanches have stepped down to this layer.The mid-December surface hoar layer is buried 130-160 cm below the surface. This layer has continued to produce step down releases and "sudden" test results. It is most pronounced at tree line, but is also present below tree line .
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: Feb 5th, 2018 2:00PM