A 91 mm rainfall in 90 minutes, accompanied by storms, caused havoc in Sydney on Wednesday, with roads going under water and airport runways having to be shut. The Sydney flash floods also hit the electricity supply with power cuts being reported from several parts of the harbour city.

With Wednesday’s downpour already equalling rainfall of the monthly average, authorities have urged people to stay safe, forecasting more rain and storms later in the day.

Over 500 people reportedly called for emergency assistance within two hours of the storms and rains on Wednesday morning, Met said.

According to the Australia’s Bureau of Meteorology, this has been the region’s wettest November day since 1984. “The intensity of that rainfall was phenomenal — 91mm fell in 90 minutes,” forecaster Rob Taggart told the Australian Broadcasting Corporation.

Quoting the authorities, media reports said at least 11 people were rescued from vehicles trapped in floods, while one man died in a car accident. Images posted online showed a flooded city — with roads, houses and train stations all under water.

There is a forecast of more rains.

“A #severe #thunderstorm which could produce damaging winds and large hail has been detected on the weather radar near Branxton. This storm is moving northeast,” Fire and Rescue Department of New South Wales tweeted.

Earlier in the day, firefighters had to negotiate flooded roads while responding to an alarm in Artarmon . “Take care if you’re travelling today and don’t enter floodwater. If it’s flooded, forget it!” Fire and Rescue NSW posted in an earlier tweet.

Reports said two police officers were injured after being hit by a falling tree while trying to help motorists.

BBC said many transport services were cancelling or delaying services. More than 50 flights were also cancelled or delayed.