What would happen if I drove into floodwater?

What would happen if I drove into floodwater?

02/02/2022, 1:34 PM

Volunteers from the Victoria State Emergency Service (VICSES) had a busy few days, responding to over 2,000 requests for assistance (Wednesday 26th to Saturday 29th January) when thunderstorms and heavy rain hit parts of the state.

Disappointingly, our volunteers received calls to 26 different floodwater rescues, prompting us now to renew our plea to reflect on the risk you place on yourself, and to never drive on flooded roads.

The temptation is somewhat understandable. Perhaps it’s been a long drive and you’re near home; you always take that route; you’re desperate to get out of the rain; you’ve done it before and got through okay, so you go for it.

It’s hard to know what is in the mind of a driver who does this but, it is clear, despite the warnings and campaigns that too many drivers continue to underestimate the risks and consequences of driving into floodwater.

Worldwide, floods are the highest cause of fatalities from natural hazards. Driving a motor vehicle into floodwater is the single biggest cause of flood deaths during Australian floods. During the period 2001-2017 there were “96 vehicle-related flood fatalities in 74 separate incidents in Australia” (source: Bushfire and Natural Hazards Cooperative Research Centre).

Flash flooding, caused by heavy rain, can happen at any time and is often made worse by blocked drains, burst water mains or toppling creeks and rivers. The floodwater flowing in front of you, in some circumstances, may have already have torn open the surface of the road.

According to a float tank experiment using real vehicles, at the University of New South Wales Water Research Laboratory, a small car can float in just 15cm of water; the height of an average pen. In the same experiment, a mid-sized car floated in water 30cm deep, and a large four-wheel drive was moved by 45cm of water. Off-road vehicles fared better, but were not immune in swift-flowing water, which can easily overcome larger vehicles depending on the speed and depth of the flow.

Rescuing stranded motorists, from floodwater, puts our VICSES volunteer crews and other responders at risk. Floodwater rescues are often dangerous and complex situations, taking priority over every other call for help we receive; given the potential risk to life. The effort of this means our volunteers delay in answering other calls for help: assisting with flooded premises, building damage or downed trees over buildings, roads and driveways.

As your vehicle floats on the surface of the water, you are vulnerable to collisions with debris. Your airbags may go off suddenly. Electrically-powered windows and locks, once disabled, make your vehicle almost impossible to escape. Even if they are unlocked, as the weight of water bears down on the body of your vehicle you may not be able to open your doors.

Even if you are rescued, your vehicle may require extensive repair. If floodwater enters the exhaust and washes into the intake, it can hydro-lock your engine causing major damage.

Because of all these reasons, we ask you take this advice: never play, enter or drive through floodwater. The risk to all is too great and may cost you your life.

For more advice on how to stay safe during flooding, please visit: https://www.ses.vic.gov.au/plan-and-stay-safe/emergencies/flood.

For information on the 15-to-float campaign, please visit: https://www.ses.vic.gov.au/news-and-media/campaigns/15-to-float.