Otto Explains — Wadis and Floods
Is It Safe to Drive Through a Wadi or Flooded Road?
Short Answer
Don’t drive into a flowing wadi or a flooded road: as little as 30 cm of flowing water can move a car, the depth and current are hard to judge, and the road underneath may have been washed away. Turn back, wait for the water to go down, and follow the warnings of the Royal Oman Police and the Civil Defence and Ambulance Authority. Deliberately crossing a wadi in a way that endangers lives is also an offence under Article 49 of the Traffic Law. If water rises around your car, switch off and call 9999, and leave the vehicle only while it is safe to do so. Water drawn into the engine can wreck it, and floodwater also damages electrics, fluids and brakes, so a car that has been in a flood should not be started until it has been checked.
Is it safe to drive through a flowing wadi or a flooded road?
No. Moving water is far stronger than it looks. About 30 cm of flowing water can be enough to move a car, and rushing water around 60 cm deep can carry away SUVs and trucks. From the driver’s seat you can’t tell how deep the water is or how strong the current is, and the road beneath it may have been washed away or collapsed. Four-wheel drive doesn’t change this: a heavier vehicle with more ground clearance can still float and be swept downstream. The safe choice is always the same: stop the car well before the water, turn back, wait somewhere safe on high ground until the water has gone down, and follow the warnings of the Royal Oman Police and the Civil Defence and Ambulance Authority, who repeatedly advise against crossing wadis. In heavy rain they also advise slowing down, keeping your distance and avoiding low-lying roads where water collects. Check the weather bulletins before a journey; the wider trip checks are in Otto’s guide to preparing for a long drive in Oman.
What does Oman’s Traffic Law say about crossing wadis?
Article 49 of the Traffic Law (Royal Decree 28/93, as amended) makes it an offence for a driver to deliberately cross wadis in a way that puts the driver’s own life, the passengers’ lives or other people’s lives in danger (item 8 of the article). The penalty is up to three months in prison, a fine of up to RO 500, or both. Police do enforce it: in June 2022, for example, the Al Dhahirah Governorate Police Command arrested a driver for deliberately crossing an overflowing wadi, and the Civil Defence and Ambulance Authority has said that driving across an overflowing wadi will invite legal action. The law is there because people die in wadis, and rescuers put their own lives at risk to reach them.
What should you do if water rises around your car?
Act early, while you still have choices. Switch off the engine (turn the ignition off) so that no more water is drawn into it, unfasten everyone’s seatbelts and call the emergency services on 9999. Leave the vehicle only while it is safe to do so: when the water around the car is still and shallow, you can see the ground, and dry land is close. Never step into fast-flowing water, which can knock an adult off their feet. If the car is caught in rapidly moving water, stay inside and call for help; if water starts rising inside the car, climb onto the roof. If the car is sinking in deep water, don’t wait for it to fill and don’t lose time on the phone: get everyone out through the windows, move away to higher ground, and call for help from there. Stopping and getting out are about staying alive; the car can be dealt with later.
What does water do to a car’s engine?
An engine breathes through its air intake, which on many cars sits low at the front. If water is drawn in, it reaches the cylinders, and a very small amount is enough to cause serious damage. Unlike the air and fuel mixture an engine is designed to compress, water can’t be compressed. When a piston tries to squeeze it, the force goes into the connecting rod, which can bend or buckle; this is called hydrolock, and it can ruin the engine. That is why manufacturers say that if the engine stops in water, you should not try to restart it: cranking it again can turn water in the intake into a bent rod. Have the car towed out of the water instead.
How does floodwater damage the electrics, fluids and brakes?
Floodwater is dirty and corrosive, and seawater is worse. A car standing in water up to its door sills can develop electrical faults, and the engine computer, sensors, wiring harnesses and connectors are especially vulnerable. Corrosion doesn’t always show at once: electrical faults can appear weeks or months later, and water in the electrics can even affect safety systems such as the airbags. How water damages the car’s electronic control modules is explained in a separate Otto article. Water can also get into the gearbox and differential and mix with their oil, which then lubricates less well and shortens their life; the engine, fuel, brake and power steering systems need the same check for contamination. Wet brakes take longer to bite, so after any drive through water, test them gently at low speed as soon as it is safe.
Why shouldn’t you start a car that has been in a flood?
Because starting it can turn damage that might be repairable into damage that isn’t. If water has got into the engine, turning it over can bend a connecting rod; if the electrics are wet, switching them on can cause short circuits in modules and wiring. A flood-damaged car should not be started until a qualified technician has inspected it, so have it recovered on a recovery truck rather than trying the key to see whether it runs. This applies even if the car looks dry from outside. If your car won’t start and it hasn’t been in water, the usual causes are covered in why a car won’t start.
Who should inspect a car after a flood?
After a flood, don’t start the car: have it recovered to the workshop. At AutoTronix, AutoTronix Lab inspects it first, because the electrics and control modules decide whether the car can be powered up safely: Lab runs a multi-system diagnostic scan across the car’s control units and traces wiring, sensor and short-circuit faults. If the inspection shows mechanical work is needed, such as water in the engine or the gearbox, AutoTronix Garage takes over. The extent of the damage, and whether repair makes sense, can only be judged once the car has been inspected.
Common Questions
- My car has four-wheel drive. Can it cross a flowing wadi? No. Four-wheel drive helps with grip, not with water: rushing water around 60 cm deep can carry away SUVs and trucks. Manufacturers’ wading guidance assumes still water at walking pace and warns against currents, and the Traffic Law offence applies to every vehicle.
- Will insurance pay for damage from crossing a wadi? Not necessarily. In 2022 the Capital Market Authority said that comprehensive cover under the unified vehicle insurance policy includes damage from disasters, but expects drivers not to cross wadis and to follow police instructions, and that deliberately crossing may lead to a claim being refused. Check your own policy with your insurer.
- Does the manufacturer’s warranty cover flood damage? Often it doesn’t. Some manufacturers exclude flood damage from the warranty; Volvo, for example, states this plainly. Check your warranty booklet or ask the authorised agent.
- My car drove through water and seems fine. Does it still need checking? Test the brakes gently as soon as it is safe, because wet brakes take longer to bite. If the water came up to the door sills, the engine stalled, or warning lights appeared, have the car inspected: electrical and corrosion faults can take weeks to show.