Loose, wet avalanche activity on sun-exposed slopes cannot be ruled out. Rime and melt freeze crusts exist. It is essential to have strong alpine skills and competency when travelling over a slick surface with high consequences. The weather is expected to be settled 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 cannot be ruled out. The surface structure will be reduced on slopes being impacted by solar radiation. The freezing levels are lowering, and cooling winds are limiting structural breakdown of the surface snow. Recommend being alert to signs of a weakening surface, such as increased foot and ski penetration and roller ball activity.
No human or naturally triggered avalanches have been reported or observed over the past 24 hours.
No precipitation has affected the snowpack over the previous 24 hours. Little change to the snowpack recently, other than a melt freeze crust developing. This crust is improving snowpack stability but increasing the uncontrolled sliding hazard. Elevated temperatures and high water content have contributed to the bonding process at the higher elevations. The snowpack is displaying signs of consolidation. A rime crust has also formed in the southwest areas, limiting snow transport. A weakness was identified at the higher elevations around Turoa today. Bridging crusts are robust, and even a significant load may not trigger a failure. A few days ago, snowfall accumulation was noted on Mt Ngauruhoe and Mt Tongariro. The south-west areas of the region have enough snow cover in isolated start zones above 1600 metres, mostly on north and west aspects. South and east aspects are still sparse at the lower elevations. In the northern areas, the threshold is at a higher elevation.
Tomorrow, the 19th of July, will have cloudy periods with isolated showers, clearing in the afternoon. The winds are moderate south-westerly, easing tomorrow afternoon. The freezing level is about 2500 metres elevation, but is lowering over the next 24 hours to 2300 metres. A west to southwest flow covers Aotearoa/New Zealand today, and a weak front moves slowly onto the far south of the country. The front moves northwards tomorrow, stalling over central New Zealand by the end of the weekend.
Recent formation of melt freeze 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, exposing an icy rime crust on slopes above 1600 metres. Numerous hazards, such as exposed rocks and cliff bands, remain present. It is essential to have strong alpine skills and competency when travelling over a slick surface with high consequences.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
