The MetService has lifted a severe weather warning for Christchurch.
The warning was issued at 2.30pm on Wednesday after the MetService weather radar detected severe thunderstorms near Rakaia and Hororata.
A fierce storm struck Timaru this afternoon, hammering the central business district with hail. Lightning strikes and thunder claps also rang out around the city.
Large hail stones began falling just before noon. The Otago Daily Times has received reports of broken windows of buildings and vehicles in central Timaru.
Allied Press Timaru sales manager Mark Julius said he had ''never seen hail stones like it''.
"It was bouncing down Stafford St . . . it was quite dramatic,'' Mr Julius said.
The hail storm lasted for about 10 minutes.
WeatherWatch NZ reported "dramatic downpours" passing over Timaru and further south in Oamaru, with one downpour blanketing Timaru in thick and heavy hail.
"The downpours may contain thunder as well but should ease this afternoon," the forecaster said.
Timaru local Ray Bailey said he'd never seen hail this big - and it was causing damage.
He said the spouting on his house looks like it had been hit by bullets.
These thunderstorms were expected to be accompanied by large hail that could cause significant damage to crops, orchards, vines, glasshouses and vehicles, and make driving conditions hazardous.
The system was moving to the northeast, and a severe thunderstorm watch remained in force for Christchurch, Canterbury Plain and High Country, and North and Central Otago.
Niwa meteorologist Seth Carrier said the conditions were similar to those that caused Monday's tornado in Christchurch. He said the hot sun was causing rising columns of air - which form serious thunderstorms.
What to do in storms
The Ministry of Civil Defence and Emergency Management advises that as storms approach you should:
• Take shelter, preferably indoors away from windows;
• Avoid sheltering under trees, if outside;
• Get back to land, if outdoors on the water;
• Move cars under cover or away from trees;
• Secure any loose objects around your property;
• Check that drains and gutters are clear;
• Be ready to slow down or stop, if driving.
During and after the storm, you should also:
• Beware of fallen trees and power lines;
• Avoid streams and drains as you may be swept away in flash flooding.
- By Rebecca Ryan and NZ Herald