The Bureau of Meteorology says it is investigating whether a tornado or waterspout tore through parts of the Illawarra over the weekend destroying dozens of roofs north of Wollongong.
Forty homes were impacted at Bellambi and Corrimal and a two-story unit block had its roof torn apart on Sunday morning.
Bellambi resident Adam Cotterill said the wind was so strong his aluminium boat was thrown into a nearby park.
"About 2:30 in the morning, all hell broke loose," Mr Cotterill said.
"I just sounded like raring thunders, like a wave coming … sort of a roar, and all-of-a-sudden just noise everywhere.
"Trees and everything were just going everywhere. There was just metal and stuff strewn all through the park.
"I came out and my tinnie was sitting in the park.
"It has just made a total mess of my whole backyard and front yard."
Mr Cotterill said it was incredible nobody was hurt.
Bureau investigates
The weather bureau said it was unable to confirm the exact cause of the damage as the event was too small and too short-lived to forecast or track via weather radars.
Investigations are continuing into whether the event was due to a tornado or waterspout. A waterspout is a type of tornado that forms over water.
"The radar imagery that we had concurrent with the time of the reports of the tornado, it will need to have a bit more investigation," Bureau of Meteorology forecaster, Helen Reid said.
"But it did look like there was a potential for an extra circulation in what was happening at the time.
The State Emergency Service said it received 68 calls for help in the area on Sunday morning and a large trampoline had to be removed from overhead powerlines.
"It certainly was an obvious trail," Southeastern Zone deputy incident controller Andrew Galvin said.
"A couple of homes had quite significant damage with roofs off and it is very difficult to do temporary repairs to a couple of them.
"So, obviously there will be conversations around the way forward for those people.
Hundreds of calls for help
SES volunteers responded to more than 900 calls for help across the South Coast, Illawarra and Southern Highlands throughout the weekend.
Some of the largest falls in the state were also recorded in the region in the 24 hours to Sunday morning.
At least 368 millimetres fell at Brogers Creek near Berry and 298 millimetres was recorded at Darkes Forest.
A severe weather warning remained in place across the region on Monday with an evacuation warning issued for several caravan parks around Lake Illawarra.
A minor flood warning also remained in place for the Shoalhaven River at Nowra and Terara and for St Georges Basin at Sussex Inlet and along Island Point Road.
