New Zealand · New Zealand Avalanche Advisory · part of New Zealand
Avalanche danger
Forecast issued 3 hours ago · valid to Sep 19
Published by New Zealand Avalanche Advisory
Wind transport may intensify with strong westerly winds on Friday, forming wind slabs during the day.
Loose wet avalanche activity may become active as the day warms up
Loose dry avalanches were very active and easily triggered on Thursday and may do the same again on Friday. They can entrain a lot of snow, easily knock you off your feet and run long distances.
Avoid narrow gullies with steep side walls, particularly when there is potential for overhead hazard.
There is currently a large fetch of recent snow, and if westerly winds pick up on Friday, we may see a lot of wind-transported snow during the day.
Treat areas of stiffer wind-driven snow on leeward slopes with caution and avoid them altogether if you see obvious signs of weakness, such as cracking or avalanches on similar slopes.
By late morning, this could become your number one problem again. Loose wet, and possibly wet slab avalanches will likely become active and start to run naturally today. Avoid travel on or under steep north aspects at all elevations as solar input increases and temperatures rise.
Be aware that these can entrain a lot of snow and run long distances.
A widespread natural cycle of loose dry and loose wet avalanches up to size 2 took place on all aspects during Wednesday evening's storm and Thursday's fine, sunny day. Some of these were not very big in size but ran very long distances.
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.
On Wednesday, around 50cm of new snow fell to very low elevations. This had some south-westerly wind effect around the high peaks and exposed ridges, where wind transport was observed over Thursday.
Before this, the snowpack appeared well settled, with no obvious or reported weaknesses. Warm daytime temperatures have been softening and turning northerly aspects below around 1900m isothermic during the day.
2-3m of new snow has fallen above 2000m since late August, with mostly rain having soaked the snowpack below around 1900m. Gale westerlies throughout the recent storm cycles have created a lot of variability in the distribution of the storm snow.
Very Large cornices have also potentially formed above 1800m.
Mt Aspiring National Park ForecastForecast
Cloudy periods with a few morning and evening showers. Snow showers to 1600 metres at night.
Wind at 1000 metres Westerly 35 km/h, rising to northwest 50 km/h late evening.
Wind at 2000 metres Westerly 60 km/h, easing to 40 km/h for a time in the afternoon and early evening.
Wind at 3000 metres Westerly gale 65 km/h.
Freezing level 1200 metres, lifting to 1800 metres in the morning.
Issued: 12:51pm Thu 17 Sep
Northerly aspects may be firm in the morning, and some exposed western aspects may be stripped back to firm ice. An ice axe and crampons could be necessary depending on your objective.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
