The heavy rain began at around 8am and lasted for about two hours, with a state official saying that 150mm of rain was recorded during that period. Penang’s average rainfall in June was 178mm and in July, 192mm, according to the ClimaTemps portal.

Many villages in Batu Ferringhi were inundated, while a major road to town was cut off.

One of the villages saw floodwaters go up by a metre, fire and rescue officials said.

A family of five had to be evacuated from Kampung Din Bamboo, while in the Sg Emas area, a monsoon drain was filled with muddy water from a construction site next to the nearby hills.

At Tanjung Bungah, horrified residents watched a stream of mud-filled water rushing down a hillslope behind a row of unoccupied bungalows. A road across these bungalows caved in about four years ago.

Today, a steady stream of water appeared to be rapidly descending a rock-faced hillslope behind the row of bungalows. The “waterfall” is a well-known feature on the hill that descends from Carla’s Peak, a popular hiking trail.

A resident said it was the first time that waters gushed so rapidly from the hill.

Trevor Sibert, who lives in a high rise across the hill near the Persiaran Tanjung Bunga 3-Solok Tanjung Bunga area, described this morning’s flash floods as “frightening” and wondered if any auditing of the hills had been done since 2017.

“We are aware of hillside property development in progress but we are wondering if any checks are being done to ensure that the safety of residents in neighbouring condominiums is not compromised.

“Judging from the muddy water, there must be something wrong with the work done. We urge the authorities to step in and immediately look into the hillside development,” he said.

Rescue officials also reported flooding at Kampung Makam near Dato Keramat. No evacuation has been reported but water appeared to have entered the homes there.