It creeps up onto the Illawarra's shores when the sun and moon's gravitational pull align - it is known as a "king tide".
Today, extra high tides swept Australia's east coast and to mark the occasion an environmental group called for photographs to document the phenomenon and raise awareness of potential effects of climate change.
Although king tides occur naturally and predictably, Green Cross Australia used its Witness King Tides project to help people visualise the potential impacts of future sea level rises.
Photographers from the Illawarra were encouraged submit pictures of the king tides along the coast, such as the Port Kembla king tide predicted to occur at 9.31am today.
Hot spots in the Illawarra included Shellharbour and the Lake Illawarra foreshore.
Green Cross Australia chief executive Mara Bun said the project was aimed at educating and engaging communities.
"Our coasts are changing with storms and sea level rise, so it's important that the Illawarra community is empowered to think ahead about choices we'll need to make in response," she said.
"Eighty-five per cent of Australians live along the coast.
"That's huge and it's very important that we think about the future of our coasts; how sea level rises could impact our homes, our infrastructure and how we live."
Since the program began in 2011, more than 4500 photos have been submitted across Australia.
Information and registration at witnesskingtides.org.