Loose wet avalanches are possible on steep slopes with a solar aspect. Loose dry avalanche concern exists above 2300 metres elevation. For the next 24 hours, the weather remains settled, with light winds and increasing cloud; however, the weather is deteriorating over the next few days.
Loose wet avalanche activity will be possible on slopes being impacted by direct sun. The low-density snow from a couple of days ago (20th July) will react negatively to solar input. It is essential to stay alert for signs of increasing surface instability. Look for point release and rollerball activity, which will indicate a developing instability.
Loose dry avalanche activity possible. The upper elevations have received 10 cm of new snow over the previous 24 hours. Loose dry avalanches will be possible in steep terrain features. Problem areas will be all aspects above 2300m over the next 24 hours. Triggering a weakness at the new-old snow interface will be possible.
Small loose dry activity noted on Girdlestone Peak in the southwest near Turoa. Estimated size 1 at around 2450 metres elevation.
No significant precipitation has affected the snowpack over the past 24 hours. A brittle melt-freeze crust has formed, capping the new snow below 2000 metres. Below this crust is a facet weakness developing, which may become problematic once loaded by additional snow. Supporting these crust facet layers is the older consolidated snowpack. New snow accumulation has most likely occurred on Mt Ngauruhoe and Mt Tongariro, adding to the existing snow cover. 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 remain sparse at lower elevations. In the northern areas, the threshold is at a higher elevation.
Tomorrow, the 23rd of July, will be fine, but becoming overcast in the afternoon. The winds are light south-westerly, tending west-northwest tomorrow afternoon. The freezing level is about 2100 metres. A ridge of high pressure lies over the North Island today, while a front will move north up the South Island and weaken. Another front approaches Fiordland from the west later today, then crosses the South Island tomorrow as the ridge moves away to the east.
Despite the recent new snow, the melt-freeze and rime crusts remain. Numerous hazards, such as exposed rocks and cliff bands, exist. Carrying an ice axe and crampons is recommended in the backcountry. It is essential to have strong alpine skills and competence when travelling over slick surfaces with high consequences.
High
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
