“A couple of areas are also under watch - Buller, Nelson Lakes and also at risk are the Canterbury lakes and the Southern Alps.”
An impressive graphic published by Government weather forecaster Niwa shows regions around Milford Sound will get 100mm of rainfall by 1am Thursday.
The lower-central western regions of the South Island, including Fox Glacier and Mt Cook, can expect the most extreme rainfall.
Niwa’s social media post describes the rainfall amounts about the ranges as “impressive”.
“Localised slips and flooding are possible,” the weather forecaster said.
The rainfall is on-trend with the nation’s wet and windy start to 2023, with flooding and cyclones hammering the North Island over recent months, causing widespread devastation.