What the Water Hides

When water covers a road, it hides the surface, the edges and anything lying beneath it. Floodwater can conceal:

• Washed-out pavement or collapsed road edges
• Potholes and dips much deeper than they appear
• Debris, branches and submerged objects
• Downed power lines
• Damage to bridges and road foundations

Moving water adds another danger. Even when it doesn’t look deep, it can push a vehicle sideways or carry it off the road. You can’t reliably identify any of these hazards from the driver’s seat.

Why Depth Is Hard to Judge

Even when water looks shallow, you can’t see how deep it gets farther ahead or whether the road beneath it is intact. The Insurance Corporation of British Columbia (ICBC), the province’s public auto insurer, warns that about 15 centimetres of water can reach the bottom of most passenger cars and may cause loss of control, stalling and damage. Around 30 centimetres can float many vehicles. These figures are warnings, not safe crossing limits. The real risk depends on the vehicle, the water and the road beneath it.

The danger is greater at night, when hazards are even harder to recognize.

What to Do When You Meet Water

If heavy rain or flooding is forecast, plan an alternate route before you leave. Avoid roads in evacuation areas and follow official travel advisories. Our bad weather guide covers hydroplaning and reduced visibility, which can come with the same storms.

If You Are Forced Into a Flooded Area

The priority is to avoid entering floodwater at all. If you find yourself approaching or already in a flooded area, don’t assume that pressing on is the safest option.

• If you can safely stop, reverse or turn around before entering the water, do so.
• Never attempt to cross moving floodwater.
• Don’t go through water of unknown depth or where the road surface is hidden.
• If your vehicle is already in the water and becomes unstable, put getting yourself and your passengers to safety first.
• Follow the instructions of emergency personnel.

Don’t treat another vehicle’s successful crossing as proof the route is safe. Water levels, road conditions and vehicles all differ.

If Your Vehicle Stalls

If your vehicle stalls in floodwater, don’t keep trying to restart the engine. Water may have entered the engine or electrical systems, and restarting could cause more damage. Your immediate priority is personal safety.

If you can leave the vehicle safely and reach higher ground without entering moving water, do so. If the water is rising, conditions are unstable, or leaving would expose you to greater danger, call 911 and follow the emergency instructions. Don’t put yourself at risk trying to save the vehicle.

Our breaking down guide covers general roadside safety.

After You’ve Been Through Water

Even if your vehicle keeps running, floodwater may have affected its brakes, electrical systems, engine or other components.

• If water entered the vehicle or may have reached the engine, don’t restart it. Arrange a tow and a professional inspection.
• If you made it through, have the vehicle checked by a qualified mechanic as soon as possible, even if it seems fine. ICBC recommends this even when the engine is still running.
• Test your brakes lightly. Manitoba’s driver’s handbook advises testing the brakes after driving through deep water, because they may pull to one side or may not work at all. Driving slowly and applying them lightly can help dry them.
• Check your insurance policy. Coverage for flood-related damage depends on your policy and the circumstances.

Common Mistakes

Judging depth by eye

The problem: The water looks shallow, so you assume the road beneath it is intact.

Better approach: Remember that you can’t see the road surface or any hidden damage. Turn around instead of estimating a safe depth.

Following the vehicle ahead

The problem: Another vehicle made it through, so you assume yours will too.

Better approach: Clearance, weight, speed and water conditions all differ. Another driver’s decision doesn’t prove the route is safe.

Driving around barricades

The problem: You think the closure is unnecessary or overly cautious.

Better approach: Treat road closures as final and find another route.

Trying to power through

The problem: You use speed to get across before the water causes a problem.

Better approach: Speed can create a wave, reduce traction and make the vehicle harder to control. Don’t attempt to drive through floodwater.

Restarting a stalled engine

The problem: You keep turning the key or pressing the start button.

Better approach: Stop trying to start the vehicle. Assess your safety, move to safety if you can, and arrange help.

Talk-It-Through Exercise: What Would You Do?

You can’t safely practise this situation on the road, so talk it through before you ever meet it.

Your job

Answer these questions out loud:

• What would I do if water covered the road and I couldn’t see the surface?
• What if a barricade blocked my route?
• What if the road ahead was flooded at night?
• What if my vehicle stalled in water?
• Where could I go to reach safety?

Your supervising driver’s job

Add a few more scenarios, such as heavy rain arriving during a trip, a flooded underpass or an unexpected road closure. Then talk through your decisions together, focusing on spotting the hazard early, avoiding unnecessary exposure and knowing when to ask for help. For more on structuring practice, see teaching a new driver.

The Bottom Line

Flooded roads are dangerous because the most important information is hidden: the road surface, its edges and what lies beneath the water. Turn around when you can do so safely. Never drive around barricades or attempt to cross moving floodwater. If your vehicle stalls, put your own safety ahead of the vehicle.

If you can’t see the road, don’t drive through the water.