Thunderstorms accompanied by intense rain and narrow belts of heavy hailstones thrashed their way up mid-Canterbury today, with some observers also reporting a tornado.
Hundreds of lightning strikes each hour lit up some districts.
"There were probably two or three storms," MetService severe weather forecaster John Crouch said today. "It's the start of the thunderstorm season in the region.
"The thunderstorms mostly affected inland Canterbury, from Geraldine to north of Rangiora, with large hail and intense rain".
"We've had reports of 2.5cm hailstones near Woodbury in South Canterbury early in the afternoon and 3cm hail near Cust, in North Canterbury, later in the day," said Mr Crouch.
"These would have been big enough to knock down crops, but they appear to have missed most of the urban areas."
The thunderstorms were relatively long-lived and travelled northwest up the Canterbury Plains, where Mr Crouch said they were normal in late December and January.
The same weather patterns could also trigger tornadoes, and there had been a report of one near Springfield, 70km west of Christchurch.
"I 've had reports of one `funnel cloud' which may have reached the ground," Mr Crouch said.
The MetService is expecting more thunderstorms tomorrow at the top of the South Island, in the Nelson area, and during the afternoon, in the Gisborne and northern Hawke's Bay areas.
