The storm was “very unusual in how widespread the severe weather is” and was a significant weather event, a release from the Met service said.
The service described the storm as “the worst of the season” and said it was the result of a low-pressure system moving up the country from Antarctica.
The National Institute for Water and Atmospheric Research said parts of the South Island could feel as cold as -20C (-4F) on Monday and Tuesday.
The storm was unusually severe for spring, the Met service said.
Thanks to Laurel for this link