Northern beaches suburbs cut off after massive ‘tropical’ downpour

The northern beaches suburbs of Whale Beach and Palm Beach have been cut off from vehicle traffic by an unusually heavy dump of rain that was close to breaking records.

A slow-moving storm dumped more than 50 millimetres of rain on the area early on Tuesday afternoon.

Flash flooding at Careel Bay on Tuesday afternoon.

The torrential rain has closed Barrenjoey Road, the only main road to the north, where it meets with Whale Beach Road, north of Avalon.

Locals warned others to take care on the Bilgola Bends. “I’ve never seen it like that before. Flooding and really dangerous. Take care,” one person wrote on the area’s Facebook page.

There had been some hail, too, to “add to the danger,” another local wrote.

The Bureau of Meteorology’s Edward Medlock said this kind of storm was unusual at this time of year, when there was little moisture in the air. Instead of moving away from the area, the storm appeared to reform over land, Medlock said.

Medlock, a meteorologist, said Great Mackerel Beach, directly to the west on Pittwater, had received the highest rainfall in the NSW network on Tuesday, recording 42.5 millimetres from 1pm to 2pm.

Over a two-hour period, it recorded 55.5 millimetres of rain, which meant it was classified as significant rainfall, which only happens about one in five years. But the deluge was less than the 67.5-millimetre threshold for heavy rainfall, which occurs about once every 10 years.

Flash flooding on Sydney’s northern beaches.

Local resident Nick Carroll, editor and director of surf report website Surfline, said the roads from Bilgola to the north were very dangerous.

He said he had driven the route from Avalon to Bilgola Bends north along Barrenjoey Road about 2.45pm, stopping at the junction of Whale Beach and Barrenjoey roads, where NSW Police were stationed.

“There is a massive lake of water over the road,” Carroll said.

Carroll, a surfer and surf writer, said the massive deluge reminded him of Hawaii, “yet it is freezing cold”.

As he headed north through Bilgola, he drove through deep water and noticed waterfalls gushing, he said.

“It feels dangerous,” Carroll said, and many people appeared to be “freaked out by the conditions”.

“It is weird, this rain is super close to the coast, and offshore the skies are blue. It is really focused on the coast, which makes it feel even more tropical.”