Heavy snow has fallen with gale force winds from the NW through to the south. The avalanche hazard has increased significantly with widespread reactive wind slab potentially producing large avalanches. Rain at lower elevations may have created a wet snow hazard. Warming temperatures may also see a wet snow hazard develop at mid elevations.
If you're planning to head into the back country take a very conservative approach, avoiding avalanche terrain and potential avalanche run outs. This situation is unlikely to improve in the next 48 hours.
Up to 1m of snow has fallen at higher elevations. Winds up to severe gale force have been observed from the north west through to the south. Expect reactive wind slabs at mid to high elevations particularly towards the main divide.
Significant rain has fallen up to 1500m creating a potential loose wet snow hazard at lower elevations. With warmer temperatures forecast this afternoon loose wet avalanches could also be possible at mid elevations.
Though there have been no reports of fresh avalanche activity in the region we would expect that the current storm cycle would have produced widespread natural wind slab and wet snow avalanches.
If you see any recent avalanche occurrences or have any relevant snowpack information or photos, you can share them via the Public Observations link on the NZAA home page.
Fresh snow fall potentially of up to 1m has fallen in the region at higher elevations, amounts taper down at lower elevations with rain falling below 1600m. This storm snow has fallen on a variety of bed surfaces - facets, wind pressed and wind stripped - and poor cohesion is likely.
Previously above 1900m: A mix of facetted surface snow and wind pressed snow existed on south aspects. This snow has largely bonded well to the old snow surface and the upper and mid pack are generally showing settled characteristics as total snow depths have increased. With continued cold temperatures some near surface faceting had been observed. With the very strong winds experienced throughout the winter there is a high degree of spatial variability in the distribution of snow and there are still areas of unusually shallow snowpack at all elevations. The lower part of the snowpack appears consolidated and unreactive. Large cornices have also formed above 1800m.
Below 1900m rain last week had saturated the snow pack creating a very stout supportive rain crust. With cold morning temperatures there was a very slick snow surface. With continued cold temperatures and a shallow snow pack some facet development has been observed.
Periods of rain, heavy in the morning. Snow lowering to 1500 metres.
Wind at 1000 metres: Westerly gale 65 km/h, rising to gale 85 km/h in the morning and then easing to 50 km/h in the afternoon.
Wind at 2000 metres: Westerly severe gale 90 km/h, easing to gale 70 km/h in the afternoon.
Wind at 3000 metres: Westerly severe gale 100 km/h, rising to severe gale 120 km/h for a time in the morning, then easing to gale 80 km/h in the evening.
Freezing level: 1800 metres.
With severe gale force winds stripping snow at altitude and rain having fallen to 1500m there will be areas of slick frozen snow surface which with cold temperatures will present a sliding hazard. Take care. An ice axe and crampons could be necessary.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
