Avalanche Forecast
Issued: Feb 29th, 2016 7:28AM
The alpine rating is Storm Slabs and Persistent Slabs.
, the treeline rating is , and the below treeline rating is Known problems includeExpect new snow to be very reactive to human triggers once it settles into a cohesive slab.
Summary
Confidence
Moderate - Timing, track, or intensity of incoming weather system is uncertain
Weather Forecast
The next pulse of snow is expected to roll in Tuesday afternoon with 15-25cm of snow by Wednesday morning. Winds pick up with the incoming storm and spike to strong out of the southwest Tuesday night. Freezing levels may also rise to around 1800m during height of storm Tuesday evening but generally remain below 1500m throughout the forecast period. We expect a clearing trend Wednesday/Thursday.
Avalanche Summary
On Sunday several skier triggered slab avalanches to size 1.5 were reported on northerly aspects at treeline and above. The avalanches were both wind slabs and storm slabs running on a new layer of surface hoar that was buried by the recent snow.
Snowpack Summary
A new layer of surface hoar up to size 20mm has been buried by the recent snow and is very reactive to human triggers. This layer is down 10-35cm and is present above 1700m on all aspects except due south where it was cooked by the sun and is a crust. Sunday's snowfall amounts varied widely across the region but were generally highest around Nelson. There was significant cross loading of slopes on Sunday so expect to find touchy wind slabs on many different aspects. These storm slabs if triggered may step down to the mid February layer that is down 80-100cm resulting in potentially very large avalanches.
Problems
Storm Slabs
Storm snow is sitting on weak surface hoar crystals or slippery crusts depending on aspect and elevation.
Use small slopes with low consequence to test reactivity of new snow.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Avoid freshly wind loaded features.>
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Persistent Slabs
Smaller storm slab avalanches may step down and awaken this sleeping dragon.
Dig down to find and test weak layers before committing to a line.>
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 1st, 2016 2:00PM