Two weeks' worth of rain fell in just four hours yesterday, overwhelming drains and causing flash floods across eastern Singapore - leaving hundreds of commuters and motorists stranded in nearly knee-high water during the morning rush hour.
Videos and photos sent in by Straits Times readers showed people wading in water near Upper Changi Road and a car stuck in flood waters outside Paya Lebar MRT station. A woman was also seen pushing her stalled car in Bedok North.
Mr Mohammad Firdaus, 33, said the junction of Upper Changi Road and Changi South Lane was flooded with water that reached knee level. While big lorries and buses could move through the water, "one of the cars looked to be stuck in the water".
The delivery driver, who has been working at a warehouse nearby for the past nine months, said: "This is the first time I have seen such bad flooding."
All in, nine areas, including Sims Avenue, Upper Changi Road and Arumugam Road near Paya Lebar were reported to have had flash floods, national water agency PUB said in a media briefing last night.
PUB noted that drainage works were taking place in eight of the nine areas.
Mr Yeo Keng Soon, its director of catchment and waterways, and a Meteorological Service Singapore spokesman said that the intense downpour that had developed quickly was the main factor in the flash floods that occurred.
The heaviest rainfall of 118.8mm was recorded at the Kim Chuan Road rain gauge between 6.20am and 10.25am. This is about half of Singapore's average monthly rainfall in January.
Rainfall at the Kim Chuan Road area, which is near Tai Seng MRT, peaked between 8am and 8.30am, with an intensity of 56mm per hour.
And the wet weather is expected to continue. According to the Meteorological Service Singapore's forecast, rainy weather is expected in the first half of this month, with rainfall expected to be above normal levels.
PUB said the wet weather conditions yesterday, due to the prevailing north-east monsoon, were aggravated by the development of a Sumatra squall over the Strait of Malacca which moved eastwards, affecting Singapore.
Its officers were deployed immediately to the nine areas to investigate and render assistance.
The first flash flood occurred at 8.30am, and all the floods subsided by 10.30am. PUB said the flash floods lasted 15 minutes to an hour.
It added that drainage works in the eight areas are expected to be completed by March next year.
By then, water can be discharged faster, reducing the chance of flash floods, said Mr Yeo. He added: "We are doing our best to expand our drain system."
The agency is, however, looking into what caused the flash flood at Tampines Avenue 12.
Mr Yeo said that preliminary results did not show any obstruction.
A possible factor is the nearby slopes where run-off rain may have aggravated the drains' capacity, causing the flash floods, said the PUB.
Those caught in the worst of it told stories about having to be rescued and needing to deal with extensive damage to their vehicles.
Mr Ricky Ng, 50, was trying to drive through the flood at Bedok North Avenue 4 at 8.45am when his car stalled.
"The engine just died and the SCDF (Singapore Civil Defence Force) had to push it - along with eight to 10 other vehicles - to higher ground near the fire station," said the head of an IT company.
Mr Ng said he was waiting for his motor workshop to assess the damage before deciding what to do. He added that he had bought a comprehensive motor insurance policy that covered flood damage.
A multi-storey carpark at Block 613A, Ang Mo Kio Avenue 4, was also hit by the heavy downpour, according to Mr Gary Haris, a senior business development manager.
The 43-year-old told The Straits Times that he saw ankle-high water rushing down the stairwells. "I had to roll up my trousers, take off my shoes and walk barefoot," he added.
PUB urged the public to exercise caution and avoid stepping into or driving into flooded areas because open drains pose a hazard when obscured by flood waters.
There were floods on 14 days last year, compared with 10 in 2016, and six in 2015. The figure has, however, dropped from 36 in 2013.
Last November, heavy rain caused flash floods in Hougang. Earlier in July, Tampines Road, and the junction of Cuscaden and Tomlinson roads were similarly hit.