Wind slabs exist on north- and west-facing slopes. These wind-driven deposits will be reactive to light loads and natural triggers such as cornice collapse. A storm system is impacting the region; gale winds, poor visibility, and snowfall are expected at low elevations over the next 24 hours. Managing increasing avalanche hazards will be challenging in this type of weather. Recommend delaying alpine travel until conditions improve.
Wind slabs are forming as new snow gets transported by strong to gale winds. The new snow will be deposited on west- and north-facing slopes. Wind slab deposits will form near sheltering terrain features and catchments. Triggering will be likely on steep start zones lacking support. If you do venture out, recommend a cautious approach to any freshly loaded slope, especially convex-shaped, high in the path.
Cornice formation possible. New snow will be transported by increasing winds over the next 24 hours. Cornice is likely to form on ridgelines with a northern aspect. Failure will be possible once weight exceeds support, triggering wind slab on the slope below. Recommend avoidance and maintaining a decent distance even after the storm event.
Several small, loose, wet avalanches were triggered by the Whakapapa ski patrol yesterday, 15th of August 2026, on steep, unsupported slopes.
At Turoa overnight, new snow accumulation was about 5 to 10cm above 1600 metres elevation. Wind slab deposits up to 30 cm are likely above 2000 metres elevation in the southern areas of the region. Typically, new snow weaknesses form within these deposits during development (expect weak layers). In the northwest of the area near Whakapapa, a limited overnight refreeze occurred. New snow accumulation is occurring above 1600 metres elevation at 1330 hours 16082026. The upper mid snowpack has an isothermal character below 2000 metres. Deeper supporting layers are consolidated to ground at 2000 metres elevation. In the northwest around Whakapapa, the snow cover and threshold have been affected by the recent rain. Threshold is now about 1750 metres in the northwestern areas. In the south-west area, the snowpack has also been saturated by rain a few days ago. This has now refrozen, locking up and leaving a melt-freeze crust which is currently being buried by the new snow. Buried crusts are helping maintain the structural integrity of the snowpack. Even after recent rain, snow cover will still exist on Mt Ngauruhoe and Mt Tongariro. If doing the Tongariro Crossing, you will be traveling over snow and ice with start zones at threshold. Recommend alpine gear and take avalanche precautions. Threshold in the southwest remains at an elevation of about 1600 metres.
Monday the 17th of August, rain easing to isolated showers in the morning. Snow to 600 metres affecting the Desert Road, clearing before dawn. The winds are southerly gales at 1200 metres elevation, but easing in the afternoon. The freezing level is 1400 metres, lowering to 900 metres over the next 24 hours. A low moves slowly away to the east of the North Island, leaving a showery south-to-southwest flow over the country today and tomorrow.
Strong winds can strip exposed slopes, making the surfaces slick and icy. Numerous hazards, including exposed rocks and cliff bands, exist. It is recommended to carry an ice axe and crampons when venturing into the backcountry. Having strong alpine skills and competence is essential for navigating over slick surfaces, as the consequences can be severe.
Low
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
