ROUGH surf, torrential rain and heavy swells have left some Northern Rivers beaches covered in a thick layer of brown foam, like a blanket of dirty snow.
While a mid-summer foam fight may look like fun, North Coast surf lifesavers are warning swimmers against playing in the frothy mess.
Far North Coast surf lifesaving director Ben Redman said people should avoid the surf as foam usually results in a large number of snake sightings.
"People shouldn't swim in it," he said. "You'll usually find a lot of sea snakes in the foam, they seem to be attracted to it."
ABOUT SEA FOAM
- IT IS created by impurities in the ocean, such as salts, natural chemicals, dead plants, decomposed fish and excretions from seaweed.
- These impurities are churned together by powerful waves, which cause the water to form bubbles.
- These bubbles stick to each other and are carried below the surface by wind currents towards shore.
- As a wave starts to form on the surface, the motion of the water causes the bubbles to swirl upwards and mass together, forming foam.
In similar conditions in 2008, one surf life saver counted 21 snakes in the foam at Lighthouse Beach in the space of a few hours.
Sea snakes are highly venomous, however they have small fangs and are generally not aggressive.
As well as snakes, the foamy surf can also contain pollution and viruses as stormwater from rivers and drains carries oil, detergents and sewerage into the sea.
Mr Redman said the foam could be hiding debris, rocks or deep water which are all potential hazards for swimmers.
Southern Cross University Marine Ecology Professor Peter Harrison said the foam was the result of heavy swell conditions and rough waves churning freshwater and seawater to form bubbles which mass together to make foam.
"There's been a lot of turbulence at sea so a lot of chemical molecules in sea water form a foam when heavily agitated."
Prof Harrison said the foam would be a mixture of algae, animal plankton, organic materials from mainland runoff during floods and other organic materials that had dissolved in the water.