What to do in case of flash floods on the road

With the onset of more monsoon rains, flash floods have become a real threat to motorists.

Avoidance is still your best option, so if you can opt to stay where you are (assuming you are in a high place that’s safe), then wait for the floods to subside.

But that isn’t always possible, so here are some helpful tips to remember when driving through flooded streets.

1. Ascertain the flood depth. Most cars have a safe flood fording depth written somewhere in the middle of the tires and wheels, or at the hub of the vehicle.

If the flood is more or less at that level, you may proceed with extreme caution. For most SUVs and pickups, the safe fording depth is usually at the floor of the vehicle, right where the doors meet the chassis sill.

But your best bet is still to check what your vehicle manufacturer says. Take note, however, that many of these ratings are for vehicles that are constantly moving through flood water; it’s a totally different ballgame when you’ve stopped in standing water.

2. Drive slowly but surely. When you enter a flooded section, drive as carefully as possible. With speeds between 5 km/h to 20 km/h, most vehicles will create a bow wave in its front as it displaces water around it, thereby creating a depression of water right in front and underneath your vehicle. This prevents water from entering the engine bay.

Too slow, and the water depression fills up quickly; too fast and the water splashes right up into the engine bay. Thus, slowly but surely is best to keep the bow wave steady and constant, and prevent it from entering the engine bay and the rest of your vehicle.

3. Do not stop when driving through flooded roads. It is absolutely important to maintain a slow and steady momentum forward so that the bow wave your vehicle makes will safely help you navigate through the flood.

Stopping will eliminate the bow wave, and water will enter your vehicle’s engine bay, and eventually, the interior, thereby damaging your car’s mechanicals and electronics.

So, before driving through flooded streets, make sure the road is clear of roadblocks that can hamper your steady progress until you hit dry land once again.

4. After clearing the flooded street/s, drive carefully for a few minutes. Your brakes will have cooled quite suddenly due to submersion in water, so you will need to slowly heat them back up to normal operating temperatures.

Dragging on them (driving forward slowly) while pressing on the brakes will heat them up, slowly remove dirt and grime from both the brake pads and discs or drums, and get them operating safely once again.

Take note that drum brakes tend to warm up longer because more water can get trapped inside the brake drum assembly.

When it’s safe to get down, check the rest of your car to make sure there are no leaves or debris blocking the radiator, or other trash that might have latched onto your vehicle.

Additionally, here are some points to consider:

1. Avoid driving through flooded streets with a current. With a strong current, as little as 12 inches of water depth can lift your vehicle off the road completely and drag it (along with yourself) towards the direction of the current.

2. Avoid driving through floods with downed electricity and telephone lines. Electricity conducts through water easily. You will be in for a rude shock!

3. Avoid driving through flooded areas with large debris. Large debris floating in flood can block your vehicle’s passage, or damage your vehicle and cause you to lose control.

4. If your car stalls in a flood, restarting it could cause huge and possibly irreparable damage. Keep this in mind. Sometimes, abandoning your car temporarily might actually be cheaper in the long run.

5. If you’re hemmed in by flooded streets, search for higher ground. Find a place to park your vehicle and keep yourself safe and dry until the floods subside.

The highest floor in a multi-level parking building is a good idea to stay safe and dry.

Of course, prevention is always key, so if you can avoid driving through floods, that’s best.

1. Check the news regularly for flood updates.

2. Find alternate routes.

3. If you’re still at home, work or school, stay there until the floods subside.

Additionally, you will need to keep your car in tip-top shape, so bear these things in mind:

1. Make sure your tires have enough tread depth to drive through water. Bald tires won’t be effective especially when the roads are flooded.

2. Pump up your tires to proper specs to help prevent damage caused by debris, hidden potholes and other obstacles and sharp objects lurking underneath and unseen due to standing water and floods.

3. Always ensure that all your lights, wipers and horns work so you always have good visibility. In case of emergency, call out for help with your horn and flashing lights.

4. Don’t forget to pack a change of clothes, a mobile phone car charger, a gallon of water, and a flashlight inside your car, regardless of the weather and situation.

And finally, if you and your vehicle are trapped in an area with flood water rising rapidly, the only thing you can do to prevent further damage to your car is to disconnect the battery terminals.

Most modern engine control units (ECU) are sealed and can withstand getting wet for brief periods, but if the current is flowing, they will get zapped and fried once the battery gets submerged in water.

Grab all your valuables if time permits, lock your car and leave for higher ground as soon as possible.

After the rains and flood subside, make sure to bring your car to the dealership or your trusted independent repair shop to give it a thorough once-over—especially if you drove through floods, whether you think your car is fine or not.

Some items might need replacing, like fluids (engine, transmission, differential, brake and clutch oils), glazed brake pads or warped brake discs, and more.

It’s always better to be safe than sorry.