Avalanche forecast

Two Thumbs

New Zealand Avalanche Advisory
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Avalanche danger

High Alpine · above 1,800 m
4 · High
Alpine · 1,200 m–1,800 m
3 · Considerable
Sub Alpine · below 1,200 m
2 · Moderate
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Highlights

Heavy snow and rain will increase the avalanche hazard on Thursday.

In the north of the region where the most snow is expected, large avalanches could run to below existing snow lines.

Hunker down and wait out the weather is the best option.

Avalanche problems

  • Storm Slabs

    • All elevations
    Likelihood
    Very Likely
    Size
    3

    Forecast snow totals are 30-120cm. Some terrain will be loaded with more than this as strong north east winds will have transported the snow to south and west facing slopes.

    Large avalanches could run naturally. It is recommended to avoid all avalanche terrain including runouts.

  • Loose Wet

    • All elevations
    Likelihood
    Possible
    Size
    2

    With fluctuating freezing levels. Mid altitude slopes may receive cycles of new snow followed by rain throughout the day.

    This is a recipe for widespread natural loose snow avalanches. Particularly where the new snow lays over older crusts.

    Avoid avalanche terrain.

Recent Avalanche Activity

A size 1.5 windslab was triggered by skiers in the Haszard Range on Monday. It was on an east facing slope at 2000m. Similar snow conditions exist on the Two Thumb Range.

If you see any activity on the Two Thumb Range, please make a public observation. It helps us to produce accurate forecasts.

Current Snowpack Conditions

Heavy snow is expected over Wednesday night and Thursday. North of Captain's Peak up to 100cm is forecast tapering to about 30-50cm in the south.

With fluctuating freezing levels, mid elevations will probably receive alternating rain and snow.

Prior to the storm the old snow pack was saturated with rain on Wednesday. It was well settled with wind blown pockets sitting over surface crusts in most places.

Snow depth varies from 40-75cm, with deeper accumulations of 100-120cm in sheltered areas.

Mountain Weather

Rain, clearing about the foothills in the evening. Snow lowering to 400 metres before dawn, affecting high-level roads, then lifting to 1800 metres from the north in the afternoon and early evening.

Wind at 1000 metres

Easterly 40 km/h, rising to gale northeasterly 70 km/h in the morning.

Wind at 2000 metres

Northeasterly 45 km/h, rising to gale northerly 65 km/h in the morning, and to severe gale 120 km/h in the afternoon.

Freezing level

1200 metres, lowering to 800 metres before dawn. Lifting to 2100 metres in the afternoon

Sliding Danger

Rain followed by heavy snow should keep the sliding danger away for the next few days.

Forecast Confidence

Moderate

  • We are confident the likelihood of avalanches will increase with the forecast weather.
  • We are uncertain about forecast precipitation amounts.
  • We are uncertain due to variable freezing levels.

New Zealand Avalanche Advisory (NZ Mountain Safety Council)

Regions covered