Wind slabs remain the primary avalanche hazard. Over the previous 24 hours, new snow and wind have impacted the region. A complex snowpack has developed. Multiple avalanche concerns currently exist. The weather is improving with a ridge of high pressure affecting the region over the next 24 hours, bringing fine and settled conditions.
Wind slabs have formed mostly on north-facing aspects. Wind slab has a hard density due to the previous gale winds, but a softer buried layer also exists (density inversion). Sheltered terrain features such as rocky catchments near ridgelines will also have wind slab deposits. Any loaded start zone lacking support will be a concern and should be treated with caution.
Cornice formations have developed. This cornice is isolated to south- and east-facing ridgelines. Cornices by nature lack support, and triggering remains possible for some time. Failure will be possible once weight exceeds support, such as additional snow loading, rain, or human activity. Recommend avoiding and maintaining a decent distance from these formations, even after a storm event.
Small-size 1 avalanche triggered on a northwest aspect at 2100 metres elevation. Triggered by Whakapapa ski patrol during slope assessment today, 05082026.
Gale winds have transported the cold, dry snow, forming a hard slab with a density inversion. These deposits have a drum-like feel when travelling over. The gale winds have also stripped and sublimated the new snow from ridgelines, exposing the rime crust. Today, very cold conditions remain. This is reflected in surface conditions with dry low-density snow persisting. In the northwestern areas near Whakapapa, a facet crust combination weakness has been noted. Questions remain on distribution and reactivity once stressed by subsequent loading. Snow cover exists on Mt Ngauruhoe and Mt Tongariro with new snow transportation observed today. These northern mountains are likely to have wind slabs also. If doing the Tongariro Crossing, you will be traveling over snow and ice with start zones at threshold. Recommend alpine gear with avalanche precautions. The south-west areas have enough snow cover in start zones above 1500 metres for avalanches to run freely (threshold). In the northern areas, the threshold is at a slightly higher elevation, but this is also changing fast. Recent snowfalls have improved snow cover overall and lowered the threshold elevation in the northern and eastern areas (about 1600 metres elevation).
Thursday the 6th of August will be settled with fine and clear conditions. The winds are moderate southerly overnight, easing and becoming light over the next 24 hours. The freezing level will be at about 800 metres, rising to 1200 metres in the morning. A ridge of high pressure expands to cover the country today, then slowly moves east tomorrow as a front approaches the South Island from the Tasman Sea.
Slick rime crusts exist. Winds have stripped ridgelines and windward terrain features, exposing hard icy crusts. Numerous hazards, such as exposed rocks and cliff bands, remain. Carrying an ice axe and crampons is recommended in the backcountry. It is essential to have strong alpine skills and competence when travelling over slick surfaces with high consequences.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
