Tropical cyclone Giselle formed in the Coral Sea near the Solomon Islands on 5 April, steering in a south easterly direction headed towards New Caledonia during the next few days. Missing New Caledonia to the west, Giselle kept moving south east and transitioned into an extratropical cyclone on 8 April.

 

Extratropical cyclone Giselle started to deepen as an upper level trough interacted with warm moist subtropical air over the Upper North Island. This was a volatile mix for what became New Zealand's deadliest storm of the 20th century. The impacts were felt country wide with the interislander 'Wahine' sunk in Wellington Harbour during the storm, with the loss of 53 lives. Wind gusts across the Upper North Island were 130km/h+ and with a recorded gust in the Cook straight of 267 km/h. Heavy rainfall caused flooding and slips country wide. 

 

 

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