Avalanche Forecast

Moderate

Unsettled conditions are expected for Thursday. Light flurries are possible in the morning and sunny breaks are possible in the afternoon. Freezing levels are expected to reach around 1800m in the afternoon and alpine winds are forecast to be moderate from the southwest. A mix of sun and cloud is expected for Friday with freezing levels climbing to around 2000m and moderate to strong southwest winds in the alpine. A weak storm pulse is forecast to bring 10mm of precipitation on Saturday but freezing levels may be well over 2000m.

Early reports from Wednesday include six size 1.5-2 natural storm slab avalanches and several size 2 explosive triggered storm slabs. These were all on southeast aspects between 1900 and 2050m elevation. The slabs were releasing on the late-February crust/surface hoar layer down 25cm. On Tuesday, four size 1 ski cut avalanches were reported. These were on northeast and east aspects between 2100 and 2200m elevation. Slab thickness was 5-15cm. On Thursday, storm slab avalanches are expected to be highly sensitive to human-triggers.  As the temperatures progressively warm heading into the weekend, the likelihood of an avalanche stepping down to the early-February weak layer may increase.

Recent storm accumulations varied widely across the region, but were generally highest around Nelson where up to 35cm of new snow was reported. Significant wind transport has been noted so expect to find deeper, more destructive slabs in exposed lee terrain. The new snow overlies a new layer of well-developed surface hoar (up to size 20mm) which is very reactive to human triggers. This layer is widespread above 1700m except on south aspects where the interface was cooked by the sun and now exists as a buried crust. 80-100cm below the surface you will likely find the mid-February crust/facet/surface hoar layer. Although this layer has become less likely to trigger, avalanches failing at this interface could be large and destructive.