Loose, wet avalanche activity on sun-exposed slopes cannot be ruled out. Rime crust is present on wind-exposed slopes. Strong technical alpine skills and competence are essential. The weather is expected to be stable over the next 24 hours, with periods of clear skies and light winds, although isolated showers may occur.
Loose wet avalanche activity on solar aspects during the warmest period of the day possible. The surface structure will be reduced on slopes being impacted by solar radiation. High freezing levels and a warm snowpack will also increase the chance of structural breakdown of the surface snow. Be alert to signs such as increased foot and ski penetration and roller ball activity.
Wind slabs may form in isolated catchments with sheltering terrain features. The hazard will be high in start zones and only dangerous in consequential terrain. If wind slabs do eventuate, they will be found above 2300 metres elevation on east and south aspects.
No human or naturally triggered avalanches have been reported or observed over the past 24 hours.
Over the past 24 hours, very little precipitation has affected the snowpack. Light rain showers have broken down the surface at the lower elevation. Elevated temperatures and high water content have contributed to the bonding process at the higher elevations. The snowpack is displaying signs of consolidation, and difficult to find any significant weaknesses currently. A rime crust has also formed in the southwest areas, which is limiting snow transport. A few days ago, snowfall accumulation was noted on Mt Ngauruhoe and Mt Tongariro. The southwest areas of the region have isolated start zones above 1600 metres and have enough snow for avalanches to run. The northern areas have a higher threshold elevation.
Friday, the 17th of July, will be mostly cloudy, with isolated light showers about the southern and western faces. The winds will be light to moderate south-westerly, tending westerly at times. The freezing level is about 2400 metres. A weak front over central New Zealand and another front over the South Island both move northeast over the country and weaken today, followed by southwesterlies. Tomorrow, a ridge of high pressure covers much of the North Island while a westerly flow affects the South Island.
Recent formation of rain and rime crusts has increased the risk of sliding hazards. Windward and exposed areas were stripped by gale-force winds during the last storm cycle, leaving an icy rime crust on slopes above 1600 metres. Numerous hazards, such as exposed rocks and cliff bands, remain present. It is essential to carry the appropriate gear, including crampons and an ice axe. Having the right skills will help reduce the chance of an accident.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
