Avalanche forecast

Arthur's Pass

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
3 · Considerable
Sub Alpine · below 1,200 m
1 · Low
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Highlights

New snow above 1700m will keep the wind slab hazard elevated for the next 24hrs. With 40+cm of snow forecast and gale winds, pick conservative routes for any backcountry travel tomorrow.

Trampers beware what is above you when crossing gullies and obvious avalanche paths. Safe travel is one at a time.

Avalanche problems

  • Wind Slabs

    • All elevations
    Likelihood
    Likely
    Size
    2

    Significant snowfalls at higher elevations have increased the windslab hazard on slopes lee to the NW, and more new snow is forecast tomorrow. While these slope are mostly in the south-easterly half, winds can 'wrap around' terrain features creating hazards in unexpected places.Monday is a day for heightened vigilance and attention to safe route selection.Beware the telltale signs of windslab including density changes (stiffer snow) and pillows or hard or 'drummy' sounding snow. Avoid convex rollovers and unsupported slopes where windslab is suspected.

  • Loose Wet

    • All elevations
    Likelihood
    Possible
    Size
    1

    Rain at lower elevations will keep the loose wet hazard a possibility. If you end up in deep, wet snow, keep out of steeper terrain.

Recent Avalanche Activity

A natural avalanche cycle is expected to have occurred during the storm.

Park user observations provide important information. Please help us.

If you see anything, please report it in the public observations section of the NZAA website.

Current Snowpack Conditions

Up to 250mm of precipitation has fallen in western areas of the Park since Friday night accompanied by fluctuating freezing levels. Most areas below ~2100m will have received a snow-rain-snow combination, followed by snow falling to ~1000m on Sunday afternoon. Snow totals remain to be determined once the storm concludes but the threshold for avalanches in western areas of the Park close to the divide is probably around 1500m, tapering to the east. A series of rain on snow events over the past weeks mean rain percolation channels will be well established in the snowpack below ~1800m and new channels will be forming to the highest elevations during this storm's heavy rain precipitation. Strong to gale winds from the northerly half will have formed windslabs on south facing slopes and around terrain features. The underlying snowpack was well consolidated prior to the storm and once drained is unlikely to hold deeper layers of concern for avalanche hazard.

Mountain Weather

Heavy rain developing in the morning, with snow to 1700 metres. Winds northwesterly at 50 km/h. Freezing level 1900 metres.

Sliding Danger

Wind stripped ridge lines and northerly slopes scoured back to old rain crusts will present a sliding hazard. An ice axe and crampons are recommended.

Forecast Confidence

Moderate

  • We are uncertain about forecast precipitation amounts.
  • We are uncertain about forecast snowfall amounts.
  • We are uncertain due to rapidly changing freezing levels.

New Zealand Avalanche Advisory (NZ Mountain Safety Council)

Regions covered