THE rain was so heavy the road disappeared beneath the torrent of water.
And the moment his foot left the accelerator, Service 61 bus driver Kan Fook Kan, 50, knew he was in trouble.
Said Mr Kan, who has been driving buses for five years and never experienced an engine failure due to flooding: "The car in front stalled so I also had to stop. When I took my foot off the accelerator, water got into the bus engine and it stalled."
It was along Tanglin Halt Road around 1.30pm. Most of the 20 people in his bus were students.
Said Mr Kan: "The road was like a river, it was covered by water. The water was flowing quite fast, it even washed away my bus mudguard, so we couldn't go anywhere.
"It was not safe to step out, we could have been swept away."
Fast, and rising too. Mr Kan said that in less than 10 minutes, the water level came up over the second step of the bus.
Luckily for him and his passengers, that was as far as it went.
Even then, they had to wait for over an hour for the rain to stop and the water level to go down before they could get off and take another bus.
In the Bukit Timah area yesterday, more rain fell than the average monthly rainfall for August for the whole of Singapore in the past 25 years.
By 4pm, the highest rainfall recorded by the National Environment Agency (NEA) was 150.8mm at the Bukit Panjang Telecom weather station.
This is higher than Singapore's average total rainfall for the month of August between 1982 and 2006, which is 143.4mm.
Some areas were hit by flash floods.
These included Commonwealth Avenue, Ganges Avenue, King's Road, Balmoral Road and Tanglin Halt, where Mr Kan was trapped.
The wet weather yesterday not only caused floods, it also sent a large tree crashing onto cars at a Bukit Batok car park.
The tree landed on five vehicles, denting four of them, and blocked the entrance of the carpark at Block 162 of Bukit Batok Street 11.
The worst hit was a small white lorry which was nearest the base of the tree.
The incident happened around 8am.
A school bus driver who gave his name as Mr Tan, 48, told Shin Min Daily News: "It was lucky that this happened in the morning. There were no passengers in the vehicles so no one got injured."
At noon, NEA's meteorological services division issued a heavy rain warning on its website.
It said: "Heavy showers with thunder is expected over many areas of Singapore between 1pm and 3pm.
"PUB says flash floods may occur in low-lying areas in the event of heavy rain. The public is advised to exercise caution and look out for flash floods."
The likelihood of flood increased because the heavy rain coincided with rising tide levels which reached a high of 2.6m at 11.45am.
NEA said wet weather is expected over the next few days, mostly in the late morning and early afternoon.
While heavy rains may continue, there are plans to reduce the likelihood of flash floods.
PUB said flash floods are expected to ease with the completion of two flood alleviation projects by the end of the year.
One project is at Commonwealth Avenue where construction work on an additional bigger canal began in August 2005.
The new canal, which costs $12.8million, will have a capacity that is twice that of the current canal.
The other project is the construction of the Marina Barrage, which will reduce flooding in the low-lying city areas.