Heavy rain means the risk of flooded roads.
While some cars will get through quite severe floods, there are a number of dangers, Apart from shorted-out electrics on petrol cars, there is also a risk of the engine sucking in water which, being incompressible will cause it to lock solid (hydraulic lock), smashing the engine.
If the water is fast-moving, there is also a risk that the car could be carried off into deeper flood water with you inside.
The only 100% guarantee to avoid being stranded if you drive through flood water is…
Don’t drive through flood water !
Find another route, 1ft of water can float a car !
The safest option will normally be to use the alternative route and you should seriously consider that, particularly if you are carrying vulnerable or nervous passengers. If, however you decide to drive through the water you should make sure there is not more than six inches of standing water or four inches of moving water. Parking up and watching other cars and trucks negotiate the flood can be a good way of checking to see how deep it is. In particular look out for hidden dips and gullies where the water could be deeper, there could be deep hidden potholes underneath.
1. Only drive through water if you know how deep it is, keep all windows shut to avoid getting water in your vehicle.
2. Drive slowly and steadily. Allow oncoming traffic to pass first and test your brakes as soon as you can after leaving the water.
3. Don’t drive through fast-moving water, such as at a flooded bridge approach – your car could easily be swept away.
4. Driving fast through standing water is dangerous – tyres aquaplane and you lose steering control. Watch out for standing water, trying to avoid it if you can, and adjust your speed to the conditions. If you experience aquaplaning, hold the steering wheel lightly and lift off the throttle until the tyres regain grip.
5. Driving fast through standing water is inconsiderate and illegal. You could face a hefty fine and between three and nine penalty points if the police believe you were driving without reasonable consideration to other road users.
6. Driving fast through standing water can cause expensive damage – the air intake on many cars is low at the front of the engine bay and it only takes a small quantity of water sucked into the engine to cause serious damage.
Remember if your still not sure after assessing it, turn around don’t drown !