Avalanche forecast

Ohau

New Zealand Avalanche Advisory
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Avalanche danger

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

New snow and strong winds are expected. Wind slabs will build on top of potentially weak layers in the snowpack.

Surface hoar and other weak crystal types have developed during the recent cold, clear weather. As new snow loads these weak layers, avalanche danger is expected to increase.

A good plan is to wait for the storm to pass and allow conditions to settle before heading into serious backcountry terrain.

Avalanche problems

  • Wind Slabs

    • All elevations
    Likelihood
    Likely
    Size
    1.5

    Wind slab danger is increasing on E–S aspects above 1800 m. Surface hoar and weak faceted snow were previously observed on shaded aspects.

    As denser new snow accumulates on top of these weak layers, avalanche danger is expected to increase quickly. Careful assessment will be required as the storm develops.

  • Loose Wet

    • All elevations
    Likelihood
    Likely
    Size
    1.5

    Loose wet avalanches are likely when rain falls onto the current snowpack. The freezing level is forecast to rise to around 2000 m on Wednesday, increasing avalanche danger on all aspects below this elevation.

Recent Avalanche Activity

Limited observations due to low cloud and precipitation.

Current Snowpack Conditions

Approximately 10–20 cm of new snow fell above 1800 m on Tuesday, accompanied by strong northwest winds. Below 1800 m, precipitation fell as rain.

Above 1800 m, the new snow was deposited onto weak faceted snow on east through south-facing aspects. Fresh wind slabs are likely to have formed in lee terrain, particularly where wind loading has been greatest.

Below 1800 m, the snowpack has become saturated by rain, reducing snow strength and increasing the potential for loose wet avalanches on steep slopes.

A further 5–10 cm of new snow is forecast on Wednesday, with continued northwest winds. This will add to existing wind slabs and may further increase avalanche hazard, particularly on lee slopes where new snow overlies weak layers.

Mountain Weather

Showers, turning to rain in the morning, possibly heavy about the Divide, easing in the evening. Snow above 1600 metres.

wind at topNorthwesterly 40 km/h.

freezing level1500 rising to 2000 metres overnight.

Sliding Danger

Firm snow conditions were present on west-facing slopes near ridgelines, with a potential sliding hazard on steep terrain.

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