Heavy snow has fallen with gale force winds from the NW through to the south. Heavy rain and snow is again forecast for today. The avalanche hazard has increased significantly with widespread reactive wind slab potentially producing large avalanches. Rain at lower and mid elevations will have created a wet snow hazard which will remain active if warm temperatures continue.
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.
Over 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 1900m. At lower and mid elevations this will have created a loose wet hazard which will remain active if warm temperatures continue.
Significant rain has fallen up to 1900m. At lower and mid elevations this will have created a wet slab hazard which will remain active if warm temperatures continue.
Weather has prevented any observations in the region for several days now. There have been no reports of fresh avalanche activity but it is expected 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 over 1m has fallen in the region at higher elevations, amounts taper down at lower elevations with rain falling below 1900m-1600m as temperatures fluctuate. This storm snow has fallen on a variety of bed surfaces - facets, wind pressed and wind stripped - poor cohesion is likely.
Previously above 1900m: A mix of faceted 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 had been observed.
Today 26 Aug
Rain with heavy falls developing in the morning, easing in the evening. Snow lowering to 1100 metres.
Wind at 1000 metres: Northwesterly 40 km/h, rising to gale 65 km/h in the morning. Changing southeasterly 45 km/h in the afternoon, rising to gale 65 km/h in the evening.
Wind at 2000 metres: Gale northwesterly 70 km/h, rising to severe gale 90 km/h in the morning, dying out in the afternoon. Northeasterly 40 km/h developing in the evening.
Wind at 3000 metres: Gale northwesterly 80 km/h, rising to severe gale 100 km/h in the morning, easing to 45 km/h in the afternoon.
Freezing level: 1700 metres.
With severe gale force winds stripping snow at altitude and rain having fallen to 1900m 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)
