Expect storm slab on most aspects at higher elevations. If westerly 1/2 winds gain force beware of windslab on lee slopes.
Lower down, a rain affected snowpack should be treated with care, especially on steep terrain and where it sits upon a snowgrass sliding surface.
Up to 35cm of new snow fell over the last three days carried by light to moderate winds. It is likely that above 1700m this has fallen fairly evenly and is present on all aspects.
Some wind transport cannot be ruled out so be wary of changes in snow density. Stiffer snow density indicates windslab development. Avoid convex rolls and steep unsupported terrain.
Below ~1700m the snowpack will have been rained on to some extent, with up to 30mm of rain in certain lower locations. If snow is wet and unconsolidated (eg, knee deep boot penetration) then you should avoid travel on steep or unsupported terrain.
No avalanche activity reported.
If you see anything, please report it in the public observations section of the NZAA website.
Up to 35cm of snow has fallen at highest elevations from the 7th and 9th August. Light to moderate winds from NW > N > NW may have transported some storm snow onto lee aspects and around terrain features. Fluctuating temperatures mean that both the older snowpack and new snow under ~1700m will have received some rain-on-snow during this time. Beneath this is a largely settled older snow pack that continues to gain strength. There are wind stripped surfaces at higher elevations on most aspects. We have limited observations of the new snow line around the forecast area, but threshold for avalanches is estimated at around 1500m in the west, tapering east. At lower elevations (below 2000m) ice crusts exist but bonding to the ice layers has been good.
Forecast for Monday 10 August
Mostly cloudy with showers, possibly heavy with snow to 1400 metres. Showers easing in the afternoon and clearing in the evening.
Wind at 1000 metres
Westerly 40 km/h dying out in the morning.
Wind at 2000 metres
Southwesterly 50 km/h, easing to 30 km/h in the afternoon and dying out in the evening.
Freezing level
1700 metres, lowering to 1400 metres in the morning.
Expect areas to be stripped back to hard surfaces from the gale winds at higher elevations. Crampons and an ice axe are a good idea, as many firmer areas now exist.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
