Driving during a flood

Unpredictable weather patterns mean we’re likely to experience storms and flooding more often in New Zealand. Here are some tips on how to drive in flood conditions.

Extreme weather is becoming more common in New Zealand. Here are some tips to prepare for how to drive through floodwaters if you encounter them.

The recent floods in Northland, Auckland, and Hawke’s Bay have highlighted the perils of driving during heavy rainfall and floods. The news has been dominated with images of vehicles almost completely submerged, or even floating in flood waters.

While we’re used to wet driving conditions in New Zealand, it’s clear that climate extremes are here to stay. This requires far greater awareness of the dangers of driving in flood conditions and torrential rain.

It can be extremely hazardous driving in flooded conditions and it’s essential to understand the risks and how to drive safely if you find yourself in a flash flood, heavy downpour, or severe storm or cyclone.

Here are some potentially life-saving and vehicle-saving tips on how to drive safely in flooded conditions, how to judge when it’s no longer safe to drive on a flooded road or bridge, and what to do if you vehicle stalls while you’re driving through deep water.

  1. Check the forecast and conditions

Driving during a flood

If you are aware of heavy rain or a storm approaching, check the weather forecast and road conditions in your area, as well as any Civil Defence or emergency services warnings. You can check New Zealand’s MetService website or app for weather forecasts and your local civil defence group or the Red Cross hazards app for alerts and warnings.

If there is a flood warning, avoid driving and, if you must drive, plan your route carefully and stay to main roads, which are more likely to be clear of floodwater due to better stormwater infrastructure.

  1. Proceed with caution

Flood and driving

If you must drive in flooded conditions, always proceed with extreme caution. Reduce your speed and maintain a safe following distance from the vehicle in front of you. Switch on your headlights but keep them on low beam, as high beam can reflect off water and impair the visibility of other drivers. Avoid quick, hard turns or sudden braking, as this may cause you to lose control of your car.

  1. Do not drive through floodwaters


If you come across a flooded road or bridge, don’t attempt to drive through the water, unless you’re absolutely sure it’s safe. If the water is more than 15cm – or halfway up your wheel – don’t take a risk and try and drive through it. Water deeper than this can make your vehicle stall, float away, or even be swept off the road by the current.

  1. Drive with caution if it’s safe

If you decide it’s safe to drive through floodwater, always proceed slowly and cautiously. If you drive too fast, the wave caused by your vehicle could drench other road users, and the displaced water could find its way into your vehicle’s engine bay.

Change into a low gear and maintain a slow, steady speed. If you drive an automatic car, you’ll often have an option to choose a low gear. Don’t stop or change gears while driving, as water may enter your engine, causing it to stall.

If you’re stuck in a queue of cars, it’s advisable for each car to pass through the water one by one. This will give you and other drivers a good idea if it’s safe to cross the flooded area or not. Also, if more than one car passes through and it’s not safe to cross, emergency services will need to rescue the occupants of more than one car in the flooded area.

  1. Crossing a flooded bridge

If you need to cross a flooded bridge, always drive with extreme caution. Before crossing, get out and check the condition of the bridge and make sure the water level isn’t more than 15cm deep. If the bridge is damaged or the water is high, don’t attempt to cross. If you’re unsure, try and find an alternate route.

When crossing a flooded bridge, always drive in the middle of the road, where the water is likely to be shallower, due to the camber. Wait for other vehicles already on the bridge to pass before crossing. Keep your vehicle moving at a steady speed and avoid sudden movements or braking.

Once you’ve safely crossed the flooded area test your brakes. This will help remove water, so they work normally again when you need them.

  1. If you get stuck in deep water

If your vehicle stops when you’re in deep water, don’t panic. Stay inside your vehicle, as it can be very dangerous to get out. Call for help from emergency services and, while waiting, switch off your engine and turn on your hazard lights.

If the water continues to rise and you feel you’re in danger, try to climb on the roof of your car and wait for help to arrive.

If your vehicle has been caught in floodwaters, it’s recommended you don’t drive it. You also shouldn’t attempt to start your it, as water could be inside the engine and electrical systems. Contact your roadside assistance or insurer for advice before attempting to drive it.

Also Read: