The last of 10,000 Ashburton homes left without power after severe gales hit yesterday should be reconnected this morning.
Gusts of up to 120kmh caused damage as a front swept through Canterbury yesterday and on to Wellington this morning.
The gales cut power to thousands of Canterbury homesand lifted a shed on to a street, while heavy rain swelled rivers to dangerous levels.
A MetService warning last night forecast thunderstorms, with large hailstones, in Canterbury tonight.
"Hailstones of this size will cause damage to crops, vines, cars and glasshouses", the warning said.
Ashburton took the brunt of yesterday's storm about 5.30pm, when fallen powerlines sparked fires and toppled trees damaged buildings, The Press reported.
A man broke his arm while on the roof of his house dealing with a damaged tree.
Heavy rain last night hammered Queenstown and the West Coast. This caused river levels to rise quickly, with the Haast River last night at 2.5m, up from 1.3m at noon yesterday. The Callery River, near Franz Josef, was at 2.5m - more than five times its usual 500mm.
Police were concerned people would be stranded by the rising waters.
"When you do get a bit of heavy rain straight after fine weather I can almost guarantee that somebody will be overdue stuck on the wrong side of the river," said Constable Sean Judd, of the West Coast police Search and Rescue team.
"The rivers certainly come up very quick around here but the upshot to that is they go down very quick, and people just need to realise that.
"Trampers just needed to wait a few hours for rivers to return to safe levels," he said.
