Surface conditions have become slick and icy in the backcountry. An uncontrolled slide will have a poor outcome. Evaluate surface conditions before committing to an ascent. A loose wet avalanche problem may develop on solar aspects, but increasing winds will counteract the surface breakdown. The weather is settled over the next 24 hours, but showers are possible, with increasing winds.
A loose, wet avalanche problem may develop with sunny periods possible. Solar aspects, mostly north-facing, will be prone to structural breakdown of surface layers. Watch for signs of solar effect such as rollerball and pinwheel activity. Gauge foot or ski penetration as you travel.
No natural or human avalanche activity has been reported or observed over the past 24 hours.
Minimal precipitation has impacted the snowpack over the past 24 hours. Not enough to decrease snowpack stability. 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 and refreezing occurred overnight. In the southwest, the threshold is 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.
Wednesday the 26th of August will have cloudy periods. A few showers, mainly from the afternoon. Snow possible to 2100 metres in the afternoon. The winds are from the northwest, moderate, increasing throughout the day, becoming strong. The freezing level is about 2400 metres. A ridge of high pressure over the northern North Island slowly moves eastwards today while a front moves onto the South Island. During Wednesday, a large trough in the Tasman Sea spreads slowly eastwards across the South Island.
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 and competence is essential for navigating over slick surfaces, as the consequences can be severe.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
