Wind slab formation will be possible as new snow starts to be transported to sheltered catchments. This problem will be found on aspects facing mostly south above 1800 metres elevation. A frontal system affects the region over the next 24 hours. Poor visibility, showers, and wind will make safe alpine travel challenging.
Wind slabs will form as new snow starts to be transported above 1800 metres in elevation. This wind slab will develop on mostly south aspects. Eastern aspects may also have wind-transported deposits. Triggering will be possible on higher-angle slopes. Sheltering terrain features such as gullies and rocky outcrops will act as catchments. These are the types of locations where loading tends to occur.
Loose, wet avalanche activity may become a possibility as rain begins to weaken the surface structure. Fluctuating freezing levels are expected to bring rain to higher elevations at times. Although precipitation is forecasted to be minimal, making deep saturation is unlikely. The surface structure will deteriorate, and isolated steeper start zones could be susceptible to triggering.
No natural or human-triggered avalanche activity has been observed or reported over the previous 24 hours.
Older wind slabs exist and are gaining strength and stabilizing. Anchors were progressively buried by the last storm cycle. Wind transported deposits on the north and west aspects now have a rime crust in the southwest areas of the region. Signs of a lingering instability were noted yesterday (12th of July) at the higher elevations. Snowfall accumulation has also been 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.
Tomorrow, the 14th of July, will have showers, with snow to 1800 metres, clearing later in the evening. The winds are strong to moderate northerlies, easing slightly tomorrow afternoon. The freezing level is about 1900 metres, lifting to 2200 metres in the morning. A broad trough moves across the South Island today, then moves over the North Island tomorrow, and is followed by a disturbed northwest flow. A front pushes onto the southwest of the South Island during the second half of tomorrow.
Windward and exposed areas have been stripped by gale winds during the past storm cycle a few days ago. This has exposed an icy rime crust on slopes above 1400 metres. Plenty of hazards, such as exposed rocks and cliff bands, remain. It's essential to carry the appropriate gear, crampons, and an ice axe. A targeted skill set will reduce the chance of an accident.
Moderate
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
