Snow and ice bore down on the US Northeast at the weekend, disrupting post-holiday airline traffic and prompting officials in New York and New Jersey to issue weather emergency declarations.

The thunderstorm that has lashed the South Island and brought widespread and large hail is one of the year's most intense storms, MetService says.

French police have detained a man suspected of attacking three women with a knife in three metro stations in the centre of Paris.

Severe thunderstorm warnings have been lifted for parts of Otago, but the South is still in line for more stormy weather going into the evening.