Three and four metre swells, 'knockout' waves predicted for east coast region

A large swell caused by a tropical cyclone in the north eastern Pacific has sparked concerns from Surf Lifesaving New Zealand (SLSNZ), who are warning the public to take care on beaches.

SLSNZ National Lifesaving manager, Allan Mundy said swells of up to three to four metres are hitting the eastern coastline this week and will affect the Bay of Plenty, Gisborne and Hawke's Bay.

Mr Mundy advises people to be vigilant when choosing a beach to swim at.

“Choose an inner harbour or local pool to cool down at, and if you are heading down to your local beach, go around low tide, especially during the week as there are no lifeguards on duty until the weekend when the volunteer services are rostered on," he says.

He also warns that the biggest danger is from "sweeper" waves that hit the beach and travel right up to the sand dunes with lots of power.

A sweeper wave occurs when two swells, operating from different weather systems like the two in the Pacific right now, combine into a larger wave – often twice the size of most other waves.

Mr Mundy says not only will they sweep all the way up the beach to the sand dunes beyond other waves, they are “at least twice as powerful” when they return to the sea.

“Another issue is the high tide, coupled with a big swell, which will catch people out while they’re walking. In most places, the combination of the swell and high tide will go right up the whole beach, right up to the sand dunes. If the dunes where you are walking are steep, you could become stranded by the water,” Mr Mundy says.

He also encouraged those going out in the water on kayaks, stand-up-paddleboards, and other small craft to avoid the eastern beaches but said if people are heading out, to make sure they are wearing a lifejacket and have two forms of waterproof communication such as a personal locator beacon and VHF radio.

Surfer footprints on sandy beach with green waves breaking at Wainui Beach, Gisborne, New Zealand
Waves (file picture). Source: