A big storm has just finished, time is needed for the new snow to settle and stabilise.
Careful assessment and conservative terrain should be in the plan for Thursday.
Above 1700m 60-70cm of new snow has fallen with strong northwesterly winds over the past 3 days. This has likely formed wind slabs on east and south-facing aspects.
Until there is evidence that this new load of snow has bonded, conservative terrain choices should be made.
With warmer temperatures and sun in the forecast for Thursday, we can expect to see some loose wet activity out of the steeper north-facing aspects. Thursday would be a good day to avoid steep terrain on these aspects.
There have been no recent observations. A cycle of natural avalanches is likely to have run during the last storm, ranging from loose wet below around 1600m and wind slabs in the upper elevation bands.
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.
60-70cm of new snow has fallen since Monday, tapering off to rain between 1500-1700m as temperatures fluctuated. Gale northwesterly winds during this time will have redistributed much of the new storm snow.
Previously on the 8th July, 5- 10 cm of new snow fell to around 900m. Gale south easterly winds during this storm stripped some exposed areas and loaded ridgetops and other terrain features. On the 5th, a notable 1-2cm rime crust formed above 1650m to the east of the region around Wanaka and may be present in some eastern areas of the Aspiring region too. Below this, 30- 50 cm of settled snow from the 3rd of July overlies a solid ice layer. A week of clear skies and cold temperatures has started to facet and weaken the strength of this shallow 50- 70 cm snowpack and should be monitored carefully once buried under the new load of snow.
Information and observations are currently very limited.
Thursday
Showers, with snow to 1300 metres, clearing to fine in the afternoon.
Wind at 1000 metres Northwesterly 50 km/h, easing to southwesterly 30 km/h in the morning.
Wind at 2000 metres Westerly gale 70 km/h, easing to southwesterly 50 km/h late morning.
Wind at 3000 metres Westerly severe gale 90 km/h, easing to southwesterly gale 75 km/h in the morning, then to 50 km/h in the evening.
Freezing level 1400 metres, lifting to 2300 metres at night.
Issued: 12:47pm Wed 15 Jul
West-facing aspects may be stripped back to firm ice at all elevations. Below 1600m where rain-soaked snow begins to freeze, conditions may also become very slick.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
