Avalanche forecast

Aoraki/Mt Cook

New Zealand Avalanche Advisory
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Avalanche danger

High Alpine · above 2,000 m
4 · High
Alpine · 1,500 m–2,000 m
3 · Considerable
Sub Alpine · below 1,500 m
1 · Low
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Highlights

With new snow and wind overnight, the avalanche hazard will be HIGH about the Divide on Friday. Avoid travel in the big mountains

Smaller snowfall totals mean the hazard is CONSIDERABLE in the Gammack, Burnett and southern Ben Ohau Ranges. Be extra conservative in this terrain as winds and precipitation intensity will vary through the storm.

Avalanche problems

  • Wind Slabs

    • All elevations
    Likelihood
    Very Likely
    Size
    3

    With intense precipitation and gale winds from Thursday afternoon into Friday, wind slab avalanches are very likely on NE to SW facing slopes near ridgeline, especially around the Divide.

    These could be large (up to size 3) near the Divide, and will be smaller as you move into the eastern part of the forecast area, but could still be large enough to bury a person.

    At this stage, a southerly change is forecast early on Friday evening. If this change arrives earlier than expected, gale southerlies could build windslab on north facing slopes. Pay attention to the wind and change plans to suit the conditions.

  • Loose Dry

    • All elevations
    Likelihood
    Likely
    Size
    1

    Loose dry avalanches are likely in steep terrain above 1500m as more snow falls through Thursday night and Friday.

Recent Avalanche Activity

No new avalanches have been observed in the last 48 hours, but observations from Wednesday were limited by bad weather.

Current Snowpack Conditions

An estimated 90cm of new snow has fallen about the Divide, tapering to 40cm in the Liebigs, and 20-30cm in the eastern part of the forecast area above around 1500m on Thursday afternoon. This snow mostly fell after gale winds eased on Thursday afternoon and overlies a mix of slick crusts in areas exposed to west and northwesterly winds, windpressed snow in deposition zones on east and south facing terrain near ridgeline, and loose, faceted powder in sheltered areas. This sits on a stout rain crust from the 24th of July below 1800m. The lower pack is generally well settled. Below 1500m the upper pack is moist from recent rainfall.

Mountain Weather

Showers, with possible thunderstorms in the morning, clearing to fine west of the Divide in the afternoon. Snow lowering to 600 metres.

Wind at 1000 metres: Gale westerly 65 km/h, changing southwesterly 40 km/h early afternoon, rising to gale southerly 75 km/h by early evening.

Wind at 2000 metres: Gale westerly 80 km/h, changing southwesterly 50 km/h early afternoon, rising to gale southerly 85 km/h by early evening.

Wind at 3000 metres: Severe gale northwesterly 95 km/h, easing to gale westerly 70 km/h late morning. Changing gale southerly 65 km/h in the afternoon.

Freezing level: 1600 metres, lowering to 1000 metres before dawn, and to 700 metres in the evening.

Sliding Danger

Ridgelines and exposed north and west facing slopes will be scoured back to slick crusts. It's probably much nicer to stay home with a cup of tea, but if you really must go into the hills, crampons and an ice axe are a good idea for ridge travel.

Forecast Confidence

Moderate

  • We are confident a natural avalanche cycle will begin shortly after the arrival of the incoming weather.
  • We are uncertain about forecast precipitation amounts.
  • We are uncertain due to the variability of wind effect on the snowpack.

New Zealand Avalanche Advisory (NZ Mountain Safety Council)

Regions covered