Rosser, B.J.; Leith, K.; Massey, C.I.; Farr, J.; Bruce, Z.R.V. 2022 GeoNet landslide response: New-Zealand-wide storm August 16–20 2022. Lower Hutt, N.Z.: GNS Science. GNS Science report 2022/60. 11 p.; doi: 10.21420/B15V-4J66
Abstract:
From August 16th to 20th 2022, an atmospheric river bringing moisture down from the tropics led to a sustained five-day period of heavy rainfall for much of New Zealand. In particular, prolonged and heavy rain fell over Northland, Taranaki, Wellington and the Marlborough and Tasman regions. Taranaki Maunga and some areas at the top of the South Island experienced up to 1.2 m of rain, and large areas in the Nelson and Tasman districts experienced rainfall totals with annual return intervals of >250 years (https://hirds.niwa.co.nz/). NIWA reported that this was the strongest atmospheric river for August since records began in 1959 (https://niwa.co.nz/news/). A GeoNet landslide rapid response (LRR) for this event was activated on the 19th of August, as several of the criteria for activating a rapid response were met. The GeoNet LRR for this event included: (1) August 19 – September 7: desktop study and formal collection of all available landslide reports for later incorporation into a national landslide database. Local Territorial Authorities were contacted to collate available local knowledge on the impacts of the event. This information was used to determine whether an escalation was warranted, and, if so, what the appropriate actions would involve. Following these activities, the main areas of concern were: Northland, Taranaki, Wellington, Marlborough, Nelson/Tasman and the West Coast; (2) August 19–24: aerial and field reconnaissance in the Nelson/Tasman region, reported on by Massey et al. (2022); (3) September 7: aerial reconnaissance of Marlborough Sounds, reported on by Rosser and Townsend (forthcoming 2022). This report covers the New-Zealand-wide landslide impacts of the August 16–20 rainfall event (auth)
