Avalanche forecast

Aoraki/Mt Cook

New Zealand Avalanche Advisory
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Avalanche danger

High Alpine · above 2,000 m
2 · Moderate
Alpine · 1,500 m–2,000 m
2 · Moderate
Sub Alpine · below 1,500 m
1 · Low
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Highlights

The NW winds are expected to increase on Friday, followed by a prolonged weather system from Saturday.

Heavy rain and snow, along with severe NW gales, are expected to continue for several days.

Avalanche danger is likely to increase significantly over the weekend.

Avalanche problems

  • Wind Slabs

    • All elevations
    Likelihood
    Possible
    Size
    1.5

    The wind slab problem is increasing as NW winds strengthen on Friday afternoon. Watch for wind transport and avoid stiff, wind-pressed snow near ridgelines.

  • Loose Wet

    • All elevations
    Likelihood
    Unlikely
    Size
    1

    Small loose wet avalanches are possible on steep, sunny slopes. Avoid steep sunny slopes during the warmest part of the day and move to colder aspects.

Recent Avalanche Activity

17 Aug: A skier triggered a Size 2 wind slab near Pioneer Hut at approximately 2300 m on a north-facing slope. See public observation.

16 Aug: Slab avalanching was generally confined to the recent storm snow, with one deeper slab observed on steep, unsupported NW-facing terrain on Mt Darwin at 2,700 m.16 Aug: Several Size 2 storm slabs were observed on south and southeast aspects in Twin Stream.

12 Aug: Heavy snow and rain overnight triggered a widespread cycle of wet loose and slab avalanches up to Size 3, mainly on south and east aspects.

Current Snowpack Conditions

Up to 30 cm of new snow fell overnight on 15 August, mainly in the southeast, with 5–10 cm on the Divide. Snow fell as low as 500 m. The new snow has generally bonded well to the old surface, with a cold clear night expected to further drying out the new snow.

Further west, a hard rain crust is still present around 2,000 m where less new snow fell. Deeper snowpack areas are generally strong, while shallow areas in the east have some faceting around crusts. This is not currently a major concern but could become reactive with a heavier load.

Mountain Weather

Mainly fine, then cloud increasing with the off showers from afternoon.

Wind at 1000 metresNorthwesterly 50 km/h, rising to gale 70 km/h in the afternoon.

Wind at 2000 metresNorthwesterly 50 km/h, rising to gale 70 km/h in the afternoon.

Wind at 3000 metresNorthwesterly 60 km/h, rising to gale 80 km/h in the afternoon, then to severe gale 100 km/h in exposed places at night.

Freezing level2100 metres, lowering to 1800 metres before dawn, then to 1500 metres in the evening.

Sliding Danger

Crampons and ice axe are useful at the moment for alpine travel. The firm rain crust is now buried by snowfall. In steep terrain or where the new snow is shallow this may be an issue underfoot or ski.

Forecast Confidence

Moderate

  • The snowpack structure is well understood.
  • We are uncertain whether the wind will be enough to form new wind slabs.

New Zealand Avalanche Advisory (NZ Mountain Safety Council)

Regions covered