Loose, wet avalanche activity cannot be ruled out. Rime and melt freeze crusts exist. It is essential to have strong alpine skills when travelling over a slick surface with high consequences. The weather is expected to be changeable over the next 24 hours. Snow showers and light winds are forecasted. Limited visibility will make negotiating hazards challenging at times.
Loose, wet avalanche activity on slopes being impacted by direct sun cannot be ruled out. Solar radiation will reduce the surface structure on these slopes. However, lowering freezing levels and cooling winds will limit the breakdown of the surface snow; it is essential to stay alert for signs of weakening. Look for increased foot and ski penetration, as well as rollerball activity, which may indicate a developing instability.
No human or naturally triggered avalanches have been reported or observed over the past 24 hours.
Very little 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. The snowpack is displaying signs of consolidation; however, facet weaknesses have been noted recently. 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.
The 20th of July will have cloudy periods with a few showers. Snow lowering to 1500 metres in the afternoon and evening. The winds will be light southerly with an easterly component to their direction at times. The freezing level is 2200 metres, lowering to 1800 metres tomorrow morning. A complex trough moves slowly northwards over the country today and tomorrow, while a ridge builds over the country, south of the trough.
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)
