How to stay safe when driving through flood water
Standing water after heavy downpours on already sodden ground is a major hazard to drivers – and one that should not be underestimated, as heavy rains sweep the British Isles
We would ordinarily recommend against travelling in conditions during which the risk of becoming stranded is great, but every year many drivers have little choice but to venture out in storms and floods. The vast majority of these journeys take place without incident, but wet roads increase the degree of risk.
Wet roads mean that stopping distances increase, while deep – even deceptively shallow-looking – water poses a particular threat to road traffic.
If you encounter floods, it’s important to approach them safely. Turning around and finding a different route is a better option than being stranded on the roof of your car for hours or, worse, being one of the flood-related fatalities that occur every year.
Modern cars are quite capable in extreme weather, but they remain especially vulnerable to water. Both the electrical system and the engine are particularly susceptible to water damage. And that’s before you take into account the immediate danger of fast-moving floodwater, which is surprisingly capable of washing a car downstream.
What should I do if I encounter a flood?
The best advice is “avoid”. If you can find a solution that doesn’t involve driving through floodwater, you minimise the risk to both you and your car. It’s almost always worth turning around and finding another route if a road is flooded – you’ll regret ruining your car for the sake of a few minutes.
You should definitely avoid driving through more than six inches of standing water, or more than four inches of moving water. Suitable footwear might allow you to gauge the depth of the flood by yourself, but a less charitable approach is to park up and observe motorists more foolhardy than yourself. See how another car gets on, and then proceed with caution (or call the emergency services if applicable).
If you decide to go through, stay on the crown of the road where possible and crawl through the water very slowly in first gear. Keep the engine revs up (by slipping the clutch if necessary) to avoid water entering the exhaust pipe. Also avoid the temptation to make a quick exit, as going at speed can push water into the engine.
Even drivers of large 4x4s should take care. Experts at Land Rover advise entering the water slowly (about 1-2mph), before accelerating to about 3-4mph. This creates a bow wave in front of the vehicle, which will create a depression in the engine bay and keep the air intake clear of water. However, this technique won’t work with old, beam-axled 4x4s, as the water tends to hit the front axle beam and squirt straight into the engine bay.
Avoid going too fast into even quite shallow puddles as that can lead to aquaplaning, where the front tyres will no longer steer the car and you lose control. It is also inconsiderate and illegal to soak pedestrians.
When you emerge from the water, dry the brakes by using them gently, and if there were leaves in the water, check the radiator for blockages.
Another thing to watch out for is irratic drivers coming the other way. You might be observing all the best advice, but big 4x4s or trucks racing though in the opposite direction can create such bow waves they drown your car.
If the worst happens and your car stops, leave the bonnet closed to avoid any further water ingress, climb out, lock the car and wade to dry land. In direst emergencies, you could try winding the car out by operating the starter in first or reverse gear but few starter motors will stand that sort of punishment so don’t rely on it.
The Environment Agency and the AA strongly advise against entering flood water that is moving or more than 10cm deep.
According to the AA, a third of flood-related deaths involve a vehicle because drivers take unnecessary risks. In 2020, it rescued almost 9,000 vehicles that had driven through or were stuck in flood water, with an estimated insurance bill of more than £34 million.
How to drive in wind
With the stormy weather the UK is currently receiving, drivers need to be careful when on the road. Gusts of wind are more common to hit your car on open stretches of road or when passing bridges or gaps in hedges. Drivers need to be conscious of tree branches and other vehicles becoming unstable in the windy weather.
Top tips for preparing your car for a windy drive
Before you even get into your car in windy conditions, it’s important to make sure that your car is properly prepared for winter weather - so that you and other road users have a safe journey.
It is important to check the following for hassle-free and safe driving during stormy weather.
Tyre tread depth - at least 3mm is recommended during winter
Tyre pressure
Fluid levels such as oil, screenwash and anti-freeze
Exterior lights
Battery - The AA confirms battery issues are the most common cause of call-outs in the winter months
Winter essential pack - shovel, torch, Hi-Vis jacket, blanket, extra layers of clothing, sturdy footwear, scraper, screenwash and refreshments
Fully clear all windows and mirrors of ice/snow
Scrape snow off the roof of your vehicle
Top tips for driving in the wind
According to the AA website, drivers must keep both hands on the wheel and be ready for stronger winds on exposed parts of the road - or when passing high-sided vehicles.
If you’re driving in windy conditions, be ready for sudden gusts when passing tall buildings too - and keep your speed down so you can stay in better control of your car.
It’s also a time to be extra mindful of cyclists and motorcyclists as they will also be more vulnerable to sudden gusts of wind. But it’s also important to keep your distance from other vehicles too.
Be aware of fallen trees - both on the road and hanging above - and use fallen twigs or small branches as a warning that there may be a larger tree further down the road.
Avoid towing high-sided trailers in windy conditions and expect lower speed limits or temporary closures due to fallen debris and accidents.
Always plan your journey carefully and check in with weather and traffic announcements as regularly as you can.
This guide has been updated with the latest advice.