Hot Canterbury weather can create high river levels

Visitors and residents of Canterbury are being urged to check the weather conditions before they take vehicles near or onto major riverbeds, particularly the Waimakariri.

This summer, there have been several instances of people being taken by surprise by rising river levels at popular recreation spots resulting in rescues.

On the Waimakariri River there are many riverbed access points – such as Kaiapoi Island, Haul Road and Harrs Road - where vehicles can potentially become stranded by rising river levels.

Environment Canterbury river engineering lead, Shaun McCracken, said large rivers such as the Waimakariri could rise rapidly despite there being no rainfall on the Canterbury Plains.

It is not uncommon for the water level to increase more than 1m in less than an hour and this could happen faster the further downstream you are.

“Hot, blustery nor-west winds in Canterbury generally mean it will be raining on the West Coast mountain ranges, with rain spilling over into the headwaters of the Waimakariri River,” McCracken said.

“After this, it can take up to 24 hours for the water levels to rise in the lower reaches of the river – and this can be a surprise to those who haven’t checked the weather and river information.”

McCracken encouraged everyone planning to access a major Canterbury river – including the Waimakariri, Rakaia, and Waiau Rivers – to check the weather ahead of their trip. River flow and rainfall data can be found on Environment Canterbury’s website.

If there has been more than 100mm of rain at Arthurs Pass, there is a high likelihood of rising water levels arriving within 24 hours downstream on the Waimakariri.

“We want people to enjoy the summer weather, but they need to be aware of their surroundings and take a safety-first approach.”

“Check the forecast and river information that is available, so you are well prepared for a day at the river and take particular care if leaving a vehicle on or a near a river bed.“