Small wind slabs formed on Friday may exist and be reactive around some isolated features.
Extra care should be taken where the runouts of even a small event are likely to be poor.
Above around 1800m, on mostly south-facing aspects, small wind slabs may have formed during Friday's light 5-10cm snowfall. Extra care should be taken around steep areas of new loading, where the runouts of even a small slide may have poor consequences.
No reports of any avalanches that have run recently, in the last 3-4 days.
Thanks for the observations that have been submited; these are very handy.
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.
Approximately 10cm of new snow has fallen above 1700m on Friday. During this time, the freezing level has fluctuated, with rain at times as high as 1800m. There has been significantly less new snow further east away from the divide. Moderate northerlies were also recorded during this time.
Before this, on 1st - 4th of August, very strong winds from the west and south have significantly stripped any exposed faces and features; other downwind areas in the lee have been left with variable surface conditions and multiple layers of very dense hard slab ranging from 10-60cm thick. Although evidence that a natural wind slab avalanche cycle took place on mostly east and southeast aspects above 1800m during the last storm and wind event, the slab now appears very stubborn and unreactive.
Very large cornices have also formed above 1800m.
The snowpack is still relatively shallow for the time of year. Approximately 60- 70 cm below 1700m and 120cm at 2000m. Crevasses are still very open, and many rock features are still visible, particularly on west-facing aspects.
Although the lower part of the snowpack also appears consolidated and unreactive, the Aspiring region is very large, and there is still limited data. Caution should still be taken, particularly in steeper, more extreme terrain where unknown weaknesses may exist.
Mt Aspiring National Park Forecast
Forecast for Sturday
Partly cloudy with isolated showers.
Wind at 1000 metres Northeasterly 30 km/h, dying out before dawn. Southerly 40 developing at night.
Wind at 2000 metres Northwesterly 40 km/h, dying out in the morning. Southeasterly 40 km/h developing at night.
Wind at 3000 metres Northwesterly 45 km/h, dying out in the morning. Southerly 40 km/h developing at night.
Freezing level 1800 metres, lowering to 1500 metres at night.
Issued: 12:53pm Fri 7 Aug
Exposed areas such as ridgelines on west and south aspects may have been stripped back to old ice layers by recent strong winds. Depending on your objective, an ice axe and crampons could be necessary.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
