Although modern cars are relatively safe to drive through standing water, floods should never be underestimated: they're still dangerous for cars and their drivers.
Not only can flood water cause irreparable damage to a cars' interior and electrical system, there's a risk of water getting into the engine and making it seize.
Fast-moving water can also put drivers at risk – in some conditions, as little as four inches can be enough to sweep a vehicle away.
1. A different route
Before trying to drive through a flooded area, always check to see if there's a different route you can take. Only attempt to cross flooded road as a last resort.
2. Stop and assess
You can never be sure of the depth of water or the state of the road underneath without taking a close look. If you are crossing at a ford, there may be a water depth gauge at the side of the road, allowing you to assess the stream’s level.
Also check the area for other hazards such as floating debris or downed power lines, where the electric current could be conducted by water.
3. Check the depth
The general rule is that you should not attempt to drive through standing water that is more than six-inches deep – so if it comes over your wellington boots, then it’s a no-go.
If it's moving, the maximum depth is even less: any more than four inches of moving water can be enough to sweep a car away into deeper flood water.
4. Take care when passing other vehicles
Avoid following or crossing against other drivers that could cause you to stray off your intended trajectory. Large vehicles are especially hazardous as they can create waves that will push the water higher than expected.
5. Aim for the highest part of the road
Usually the highest part of the road will be in the middle (called the crown), as most roads are designed to let water drain off the sides. Make sure you keep your eyes peeled for hidden dips (such as potholes, gullies and trenches) where the water could suddenly get deeper.
6. Stay in first gear to keep your speed down
Richard Price, chairman of Sussex 4x4 Response
, an organisation that provides assistance to the emergency services and local authorities in adverse weather conditions, recommends you enter the water at 1-2mph.
“Hitting the water at speed could cause the car to aquaplane, which is when the wheels lose their traction and the driver loses control,” he says.
7. Keep your car revving
Once in the water, try and keep the revs up. This will avoid water being sucked back into the exhaust.
“You can accelerate up to 4-5mph as this will create a small wave, protecting your car’s engine from the worst of the water,” says Richard Price.
If you drive a manual and you find keeping the revs high is making you go too fast, try slipping the clutch.
8. What to do if you stall
The most important thing to avoid while clearing a flooded section of road is stalling. If this happens, it's important to try and start your car straight away, as the longer you wait, the further the water will be creeping up your exhaust system.
9. Dry your brakes
Normally if you follow steps one to eight you should make it out of the other side of the flood, but that doesn’t mean you're in the clear yet.
It's important to remember your brakes will be wet and in order for them to work properly you need to dry them.
For the next few miles, drive slowly and regularly apply the brakes lightly to heat them up and help the water to evaporate.
10. What to do if your car stops
If your car does stop in the flood, you should climb out and lock the doors before wading to solid ground.
It may seem drastic to abandon a stranded vehicle, but in these situations, personal safety is the most important thing.
Modern vehicles are surprisingly resilient when it comes to water damage and can withstand more than you'd expect, but for peace of mind, consult your car insurance
provider about their breakdown cover