Big surf to reshape Sydney beaches after ‘wave drought’

2 hours ago 2

A short-lived coastal storm will stir up the surf on Sydney, Illawarra and South Coast beaches this weekend, creating waves as high as four or five metres that will cause dangerous conditions for swimming, rock fishing and boating.

Beach scientist Andrew Short said the big waves would start reshaping beaches for more consistent surf after a period dominated by small waves breaking on shore. The “wave drought” this summer has been interrupted only occasionally and briefly, Short said.

Paddle boarders in small surf at Manly on Wednesday.

The Bureau of Meteorology has issued a hazardous surf warning for the coast from Eden to the Illawarra for Friday, and this will extend to Sydney by Saturday. NSW Police marine area command advises people to stay out of the water. Damaging surf conditions that may lead to coastal erosion and localised damage to coastal infrastructure are expected between Eden and Ulladulla from Friday afternoon.

It qualifies as a coastal storm when waves are more than three metres high and last for more than 24 hours. The forecast is not predicting the monster waves of some previous east-coast lows, which are often seven or eight metres high, especially in winter, or the notorious 2015 storm when 14.9-metre waves pummelled Narrabeen.

Senior meteorologist at the bureau Angus Hines said the waves would peak at about four metres at the coast, including Sydney beaches, with five-metre waves a bit further offshore.

“They tend to shoal a little bit as they come onto the beach, so you might not see four metres if you’re standing on the beach and seeing it crashing, but still, some very powerful waves will be landing on the beaches,” Hines said.

The University of NSW Water Research Laboratory is predicting the wave height to peak at 4.26 metres off Sydney beaches at 10am on Sunday, shortly after high tide, with the storm to last 50 hours.

UNSW Professor Kristen Splinter, managing director of the lab, said the waves would come from the south-east and wrap around the coastline.

“Beaches that are more south-east-facing are going to be more prone to bigger waves that are coming from the south-east,” Splinter said. “The ones that are more north-facing are fairly sheltered.”

Short, an honorary professor of coastal geomorphology at the University of Sydney, said small waves that break on the shoreline had been dominating Sydney beaches for most of the summer, much to the disgust of surfers.

Swimmers ready for the daily Bold and the Beautiful swim from Manly to Shelly Beach.

Short said months or weeks of small waves under a metre high carried sand to the shore, creating a shelf that immediately dropped off into deep water with no surf zone.

“We had a fairly benign winter going into summer with no major storm events, just moderate to low waves, and as a result of that the sands returned to the shore, the sandbars are disappearing and when the waves do break they’re not very big,” Short said. “We’ve got what the surfers call a wave drought.”

Short said a sustained period of waves bigger than about 1.5 metres would drag the sand offshore to form sandbars and provide good surf. This weekend’s storm would start to reverse the sand build-up and the bigger waves forecast for Sydney next Thursday and on January 27 would help maintain the gains.

“We could have a moderate resetting of the sandbars, plus bigger waves will make them more surfable, so there may be some reasonable surf over the next 10-plus days,” Short said.

Short said he agreed with Herald writer Malcolm Knox, who wrote in a column last week: “More sad surfer faces: Manly has become Coogee.”

Peter Anthony, 66, who has swum and surfed at Manly his whole life, said he had experienced waves “bigger than ever” on some days this summer, especially a few weeks ago, but noted that conditions could vary hugely.

“The reason we love the ocean is because it’s always different,” Anthony said. “It can be dramatically different on a single day. Even [on Friday] morning we had fairly big waves early, at about 6.30am, and then it dropped probably by about a metre or so as the tide was going out.”

Members of the Bold and the Beautiful swimming club setting out from Manly to Shelly Beach. The small waves make it easier for ocean swimmers to get past the break.

Anthony, who does the return swim to Shelly Beach with the Bold and the Beautiful swimming club most mornings, said he enjoyed swimming in waves but not once had they exceeded three metres. For surfing he liked them “the bigger, the better”.

Seven people drowned swimming or boating in rough surf in NSW over the four days from December 31 to January 3, Royal Life Saving figures say.

But the big waves did not last long enough to reverse the build-up of sand on the beaches and form sandbars, Short said.

Hazard surfing warning - advice from NSW Police Force, marine area command

People should consider staying out of the water and avoid walking near surf-exposed areas.
Rock fishers should avoid coastal rock platforms exposed to the ocean and seek a safe location that is sheltered from the surf.
Boaters planning to cross shallow water and ocean bars should consider changing or delaying their voyage.
Boaters already on the water should carry the appropriate safety equipment and wear a lifejacket.
Boaters should remember to log on with their local marine rescue radio base, via VHF Radio or the Marine Rescue app, and consider their safety management plan.

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