Sydney storm aftermath: battered city recovers after extreme weather

Zaza Silk, whose swimming pool was left lying on the beach after erosion at Collaroy, has told Network Ten's The Project she is devastated.

Ms Silk moved into the beachfront home three years ago using inheritance from her mother, and kept an urn of her mother's ashes in the yard, which was also the resting place for her recently-departed dog.

As rough seas moved in she watched as the yard was washed away, in a situation she says the Council could have stopped.

"There was a big crack in the ground and then that started going beneath us, and slowly the sea encroached upon our property," Ms Silk said.

"The Council have known about this for a long time, and they should've put a wall up before then. They've known that the land there is unstable ... this could have been avoided."

Dr Mitchell Harley, a senior research associate at the University of New South Wales, is at Collaroy where the homes are breaking apart.

He has told Fairfax Media the situation is "very serious".

"Some houses are starting to break up," he said on Monday night. "It's eroded a further five or so metres and there's a very huge concern that these houses won't survive the night. They're very much teetering on the edge.

"There's large cracks being heard as the buildings are starting to break away."

Dr Harley said the tide was crashing and creating splashes "that are going higher than two-storey buildings".

"Police are keeping a lot of people away."

Tonight's king tide has destroyed seven homes at Collaroy.

Sources have confirmed to Fairfax Media that the homes are "gone" and a beachfront block of units is under threat by severe erosion.

The king tide is now beginning to impact the wider NSW coast and the already-damaged areas of Collaroy and Narrabeen.

Dr Mitchell Harley, a researcher at the University of New South Wales, says the situation for Collaroy is "extremely serious" with erosion continuing.

This time lapse gif shows exactly how much sand has already been eroded in the last 72 hours, leaving a backyard swimming pool sitting on the beach.

Events like this weekend's super storm are likely to become fewer in frequency in a warming world but pack more intensity when they hit, climate scientists say.

The severe coastal erosion and flooding came just a month after the NSW government announced increased funds and a new coastal management bill to require councils and residents to prepare for emerging threats.

The source of the wild winds, heavy rain and coastal erosion was an east coast low. Such storms are typical at this time of year, with as many as eight such lows a year.

Residents are allowed to go back to their homes in Narrabeen after an emergency evacuation order, which was put in place on Sunday, was revoked on Monday evening.

Police said residents going back home should be aware of risks like structural damage, live power, and any free-flowing effluent that may be in the water.

The emergency evacuation order for identified properties along Pittwater Road at Collaroy remains in force until further notice.