Wind slab formation remains a possibility at the higher elevations. A loose-wet problem also exists on lower slopes due to rain saturation. The weather will be changeable over the next 24 hours with periods of poor visibility and strong winds at times. Managing alpine hazards will be challenging during these weather conditions.
Wind slab development on southern aspects above 2000 metres is possible over the next 24 hours. Once the new snow starts to get moved around, wind slab deposits will form near sheltering terrain features and catchments. Triggering will be possible on steep start zones lacking support. The loose snow available for transport will be low volume, but even 5 cm of new snow can equate to a 15cm slab once transported by wind.
Loose wet avalanche activity is possible over the next 24 hours. Rain will reduce the structural integrity of the surface layer. Any steep slope lacking support will become prone to loose wet avalanche activity. Visibility could be poor at the higher elevations, hindering slope assessment and navigation. Signs of a developing surface instability are roller ball and point release below cliff bands. Monitor foot penetration and precipitation.
No natural or human-triggered avalanche activity has been reported or observed over the past 24 hours. Visibility has been poor at times, preventing comprehensive observations.
Snowpack surface layers were saturated by rain over the past 24 hours. The weather stations (telemetry) have recorded about 25 mm of precipitation at 2000 metres elevation at Turoa and Whakapapa. Standard observations were conducted this morning, typically around 9 am. Additional rain has since affected the snowpack below 2000 metres. Current snowpack is draining well, with no signs of structural collapse observed today. There was a report of new snow accumulation at the top of the Knoll Ridge at Whakapapa at 2300 metres. This new snow was bonding well to the old surface due to the elevated temperatures. Buried crusts help maintain the structure of the snowpack. No significant weaknesses currently exist; however, some isolated facet layers have been noted on shady aspects. Snow cover exists on Mt Ngauruhoe and Mt Tongariro. If doing the Tongariro Crossing, you will be traveling over snow and ice with start zones at threshold. Recommend alpine gear and take avalanche precautions. Threshold remains at an elevation of about 1600 metres. But if it keeps raining, this will change.
Friday the 14th of August will have periods of rain with snow to 2000 metres. The winds are strong northeasterly, easing in the afternoon. The freezing level is about 2400 metres elevation. A broad trough covers most of New Zealand today, while a low approaches the upper North Island from the Tasman Sea. On Friday, the low and associated trough move over the upper North Island, while another front approaches the lower South Island later.
Strong winds can strip exposed slopes, making the surfaces slick and icy. Numerous hazards, including exposed rocks and cliff bands, persist. It is recommended to carry an ice axe and crampons when venturing into the backcountry. Having strong alpine skills and competence is essential for navigating over slick surfaces, as the consequences can be severe. Leaving the surface slick and icy. Numerous hazards, such as exposed rocks and cliff bands, remain. 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.
Low
New Zealand Avalanche Advisory (NZ Mountain Safety Council)
