A van ended up on its side in a ditch during a freak hailstorm in North Otago yesterday.
Emergency services were called to the single-vehicle crash on State Highway 83 between Glenn Settlement Rd and Aitchison Rd at Awamoko, about 30km northwest of Oamaru, about 12.40pm.
Two people were treated for minor head injuries by St John at the scene, before being transferred to Oamaru Hospital.
Senior Constable Ruth Perham, of Oamaru, said the driver was caught by surprise by the intensity of the hailstorm.
''It was very sudden. There was a very large hailstorm ... there was a blanket of hail on the road about 2cm deep.''
A nearby farmer, who did not witness the crash, rushed to help when he noticed the vehicle had flipped.
Snr Const Perham said the couple were left shaken.
One lane of the highway had been closed for about an hour after the crash while it was cleared.
Although North Otago experienced thunderstorms with hail yesterday, it was not on the same level as that seen in Timaru, where it was reported hailstones bigger than golfballs pelted the town.
Niwa meteorologist Ben Noll said yesterday's atmosphere provided the ''right environment'' for hail.
''We've got cold air in the upper levels of the atmosphere.
''At this time of year the sun-angle is increasing a lot so that allows the ground to heat up quite rapidly and the combination in the upper levels and the warmth in the ground - that can contribute to rising motion, or wind, in the atmosphere.''
The Canterbury plains were the meeting point for winds from the interior of the country and coastal winds, which created instability, and sent hailstones towards the ground, Mr Noll said.
''All systems are go at the surface, and up above us, for thunderstorms above us for the eastern South Island.''
