Generally, it is not safe to drive through a flood. ST PHOTO: CHONG JUN LIANG

Singapore experienced flash floods caused by heavy rains on Friday (Aug 20). Vehicles were partially submerged at the junction of Tampines Avenue 10 and Pasir Ris Drive 12 and were unable to move, said the Singapore Civil Defence Force (SCDF) in a statement.

What should you do if your car is near a flash flood, or if you’re driving through a flash flood?

Here are answers to some questions.

Q. How do I know whether I can drive through a flash flood?

It depends largely on the amount of ground clearance that one’s car has, said The Straits Times’ senior transport correspondent Christopher Tan.

Generally, it is not safe to drive through a flood. A typical family car has a ground clearance of 120 to 140mm, which is not very high.

But if necessary, one should gauge the water depth by looking at the road curbs. If the curbs are still visible or just below water level, it is relatively safe to proceed.

If the curb is not visible, it is riskier to proceed unless you are in a tall vehicle like an SUV or a truck. Otherwise, you may end up driving into a drain, canal or over a ledge.

Q. What should I do when driving on a submerged road?

Drive very slowly and steadily in a low gear to keep your engine speed high and constant until your car is out of the water, suggests the Automobile Association of Singapore (AAS).

This prevents water from entering the exhaust pipe, which will damage electronics. Driving slowly also reduces the risk of losing steering control.

To avoid stopping in the middle of the flood, allow oncoming traffic as well as vehicles going in the same direction to pass.

Do not lift your foot or apply brakes midway to minimise turbulence and backflow that can lead to water intake.

After clearing the flooded area, apply the brakes gently for a few minutes to rid them of moisture, which may have impacted their performance.

Q. What should I do if my car stalls while driving through a flash flood?

Do not attempt to restart it as that may damage the engine, said the AAS.

Ensure the car’s bonnet is closed because you may have difficulty restarting the engine.

Switch on the hazard lights to alert other drivers around you and call for help.

Q. Should I abandon my stalled car?

It is important to leave the car and get to higher ground if the water level reaches the bottom edge of the car door, said the AAS.

Avoid waiting for the car to get submerged as the doors may not open and you will be trapped inside.

Moving water at a depth of 15 cm can make it unstable for an adult to walk.

Upon exiting the car, call for a tow truck to avoid causing congestion on the road.

This article was first published in The Straits Times.