Loose wet avalanche activity is possible. Light rain will weaken the surface snow, increasing the likelihood of triggering avalanches on steep slopes. The weather is changeable over the next 24 hours with showers and poor visibility. Navigation and identifying hazards will be challenging when visibility is limited.
A loose, wet avalanche problem will develop on steep unsupported slopes. Light rain is likely at the higher elevations. This will eventually affect the surface structure, breaking down the surface layers. Watch for signs such as rollerball and pinwheel activity.
No natural or human avalanche activity has been reported or observed over the past 24 hours.
Minimal precipitation impacted the snowpack overnight, but light rain is affecting the snow surface currently (1400 hr 260820260). The rain started around midday at Turoa. Not enough rain to reduce snowpack stability at this stage. The deeper supportive snowpack is currently consolidated with no significant weaknesses identified but is heading isothermal at the lower elevations. Melt-freeze conditions exist in the northern areas, as surface breakdown occurred yesterday with refreezing overnight. The threshold is now about 1800 metres in the northwestern areas. Snow cover will exist on Mt Ngauruhoe and Mt Tongariro. Snow and ice are present on the Tongariro Alpine Crossing. Alpine skills and equipment are essential to hike this track. If doing the Tongariro Crossing, you will be traveling over snow and ice with exposure to start zones at threshold. Recommend alpine gear and take avalanche precautions. The threshold in the southwestern areas is at an elevation of about 1700 metres.
Thursday the 27th of August will be mostly cloudy with showers. The winds are moderate westerly, easing for a time during the day. The freezing level is at about 2400 metres. A ridge maintains across the North Island while a trough in the Tasman Sea spreads slowly eastwards across the South Island today. The trough deepens offshore Fiordland on Thursday, while the ridge over the North Island moves east.
An overnight refreeze has occurred, resulting in a slick, icy crust. This will increase the chance of a sliding accident. 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 is essential for navigating over slick surfaces, as the consequences can be severe.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
