We are in the largest storm of the winter. Heavy snow has fallen with gale force winds from nearly all directions. Heavy rain and snow is again forecast for today. The avalanche hazard remains high with widespread reactive wind slab potentially producing large avalanches. Rain at lower and mid elevations has created a wet snow hazard and warm temperatures forecast for the afternoon will see this become increasingly reactive.
Avoid travel in avalanche terrain. This situation is unlikely to improve in the next 48 hours.
Over 1.5m of snow has fallen at higher elevations. Winds up to severe gale force have been observed from nearly all directions. Expect reactive wind slabs at mid to high elevations particularly towards the main divide. With the volume of snow fallen these slabs could produce large avalanches running full path.
Significant rain has fallen up to 1900m. Rain at these lower and mid elevations has created a loose wet snow hazard and warm temperatures forecast for the afternoon will see this become increasingly reactive.
Significant rain has fallen up to 1900m. Rain at these lower and mid elevations has created a wet slab hazard and warm temperatures forecast for the afternoon will see this become increasingly reactive.
Weather has prevented any observations in the region for several days now. There have been no reports of fresh avalanche activity but the current storm cycle will 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 1.5m 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 27 Aug
Rain, heavy from late morning. Snow lowering to 800 metres for a time in the morning and afternoon.
Wind at 1000 metres: Gale easterly 65 km/h, rising to gale northeasterly 85 km/h early afternoon, easing to northerly 50 km/h at night.
Wind at 2000 metres: Northeasterly 45 km/h, rising to severe gale 110 km/h in the morning, easing to gale northerly 70 km/h at night.
Wind at 3000 metres: Northerly 40 km/h, rising to severe gale 110 km/h in the morning, easing to gale 80 km/h at night.
Freezing level: 1400 metres, lifting to 2300 metres in the afternoon.
With severe gale force winds stripping snow at altitude and rain having fallen to 1800m there may be areas of slick frozen snow surface which with cold temperatures would present a sliding hazard. Take care. An ice axe and crampons could be necessary.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
