Wind slabs will form rapidly on northern aspects. New snow avalanche hazards will develop as the weather deteriorates over the next 24 hours, bringing snow, poor visibility, and gale winds. Managing increasing avalanche hazards will be challenging in this type of weather. Recommend delaying alpine travel until conditions improve.
Wind slab development could be rapid as weather deteriorates over the next 24 hours. Any new snow will immediately get transported to 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. 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.
Small loose wet avalanche activity reported as naturally triggered today, 15082026. Multiple small slab avalanche activity reported from Turoa. These events were naturally triggered sometime over the past 48 hours above 1800 metres elevation with a south-southeast aspect.
Once again, no overnight freeze of the snowpack at Whakapapa below 2000 metres elevation. Warm overnight temperatures and elevated freezing levels have prevented a refreeze, resulting in a wet, slushy surface layer. The mid snowpack is made up of crust layers that are mostly enhancing stability. 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. Around the southwest, the snowpack has also been saturated by rain over the past 72 hours. This has now refrozen, locking up and leaving a melt-freeze crust at the surface. Current snowpack seems to be draining well, with no signs of structural collapse being observed. Buried crusts are helping maintain the structural integrity of the snowpack. No significant weaknesses currently exist. 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.
Sunday the 16th of August will have periods of rain. Snow to 1700 metres at first, then lowering to low elevations by morning, affecting the Desert Road. The winds are strong southeasterly, possibly gale at times, tending southerly throughout Sunday. The freezing level overnight is 2000 metres, lowering to 1200 metres in the morning then to 900 in the evening. A low and associated fronts move slowly east across the northern North Island today, while another front moves north over the South Island and onto the southern North Island. Tomorrow, the low moves slowly east, leaving strong southerlies over the North Island.
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.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
