Shore Road landslide

The 2023 January 27 Auckland Anniversary storm was from an “atmospheric river,” dumping Summer’s worth of rain (265 mm) in one day. This was the highest 24-h total on record, estimated a 1 in 200-year event. The peak 2-min rainfall in Māngere close to Auckland Airport was 4.2 mm (24-h total of 265 mm), causing flash flooding around 5 pm, and cancelation of the Elton John rock concert, leaving many people stranded near the Mt Smart stadium venue. The storm meant that January 2023 was the wettest month ever (539 mm) in central Auckland, easily exceeding the previous record of 420 mm in February 1869 (NIWA 2023). This led to widespread landsliding throughout Auckland, including a fatal landslide in Parnell, central Auckland. Notably, this occurred only meters from a similarly destructive landslide in 1997. At Parnell in central Auckland, a fatal landslide occurred at 33 Shore Road. This was a slump within the upper cliff, formed of Waitemata Group East Coast Bay Formation residual soil and weathered rock. Following the classification of Hungr et al. (2014), this was probably initiated as a clay/silt rotational slide that transitioned downslope into an earthflow, with a Fahrböschung angle of ~32°. This landslide inundated the house below, which had been constructed, in part, on colluvium formed from prior slope failures, and extended onto Shore Road itself