Heavy rain in Sri Lanka can reduce visibility and flood a road within minutes. The most important rule in this guide is simple: do not drive into floodwater. The rest covers when to expect heavy rain, how to prepare your car, how to drive on wet roads, and what to do if you get caught out.

When to expect heavy rain

The Department of Meteorology divides Sri Lanka’s year into four rainfall seasons:

SeasonMonthsWhat to expect
First inter-monsoonMarch to AprilAfternoon and evening thunderstorms
Southwest monsoonMay to SeptemberRain mainly in the southwest and on the western slopes of the hill country
Second inter-monsoonOctober to NovemberThunderstorms and heavy rain across much of the island
Northeast monsoonDecember to FebruaryRain mainly in the north and east

These are patterns, not promises. Severe weather can come outside them, so check the forecast before a long trip.

Where to check for warnings

If a warning covers your route and the trip can wait, wait.

Prepare the car before the rain

Tyres. Worn tyres skid more easily in the wet, because the shallow grooves clear less water.

  • Find the small raised wear bars inside the main grooves. If the tread has worn down level with them, replace the tyre immediately.
  • Many tyre guides recommend changing well before that, at about 3 mm, because wet grip falls as the tread wears.
  • Set the pressure to the figure on the sticker in the driver’s door frame or in your owner’s manual, and check it when the tyres are cold.
  • Look for uneven wear, which can point to an alignment or suspension problem.

Wipers and washers. Replace the blades if they smear, streak or judder, and fill the washer bottle. Do it before the season starts instead of waiting for the first downpour.

Lights and brakes. Check that all your lights work, including brake lights, and have the brakes looked at if the pedal feels different or the car pulls to one side.

Air conditioning. Make sure it clears a misted windscreen quickly. Heavy rain and a full car will fog the glass, and a rag is not a safe substitute while you are moving.

Emergency kit. Keep a phone charger, torch, drinking water, a basic first aid kit and a cloth in the car.

Insurance. Ask your insurer in writing whether your policy covers flood damage and any other natural perils. Don’t assume it does.

Driving on wet roads

Slow down and leave more room

Stopping distances are at least double on a wet road, and worse in standing water. Slow down to suit what you can see, and double your following gap. If you normally keep two seconds behind the vehicle ahead, keep at least four.

Make everything smooth

Brake, steer and accelerate gently, and earlier than you normally would. Sudden inputs are what usually break the tyres’ grip. Take extra care in the first rain after a dry spell, when oil and dust on the surface can make the road especially slippery.

Be seen

Use your dipped headlights whenever it rains hard, including during the day. Don’t use high beam, because it reflects off the rain and makes it harder to see. Hazard lights can hide your turn signals, so keep them for when you have stopped.

Watch for what the water hides

Water can cover potholes, open drains, fallen branches and washed-out road edges. Stay away from the edge of the road, and don’t assume a familiar road is the same as it was yesterday.

Motorcycles and three-wheelers can lose grip and change direction suddenly in the wet. Give them plenty of room, and watch for pedestrians, who are harder to see at night and may step out to avoid puddles.

When you can’t see

If the rain is too heavy to see the road properly, stop as soon as you can do so safely. Pull well away from traffic, ideally at a fuel station or car park, and put your hazard lights on while you wait. On an expressway, leave at the next interchange or service area if you can. Avoid stopping beside rivers, on low ground, or under trees and steep slopes.

If the car aquaplanes

Aquaplaning is when the tyres ride on a film of water and lose contact with the road. The steering goes light, and the engine may rev higher.

  1. Ease off the accelerator gently.
  2. Don’t brake hard, and don’t make any sudden steering movements.
  3. Hold the wheel steady until the tyres grip again.

The best protection is prevention: slower speeds and good tyres.

Floodwater: turn around

Most of the danger in a flood comes from what you can’t see. You can’t tell how deep the water is, how fast it is moving, or whether the road beneath it is still there, and the surface won’t tell you. Another vehicle getting through proves little, since it may be taller or have got through before the water rose.

  • Moving water: never enter it. Rushing water can sweep a vehicle away at depths that look harmless, and about 30 cm of water can float many cars.
  • Barriers and warnings: never drive around them. Turn back and find another route.
  • Water covering the whole road: turn around. A delay costs far less than an engine or a life, and water drawn into the engine can destroy it.

If you have no way around and the water is shallow, still and over a stretch you can see across, wait until the road ahead is clear, then cross slowly and steadily so that you don’t push up a wave. Don’t stop or change gear halfway. Afterwards, drive slowly and brake gently a few times until the brakes feel normal.

If in doubt, don’t cross. Hybrid and electric cars are no exception. They are fine in normal rain, but they should not be driven into deep water, and a flooded one is an electric shock and fire risk.

If you stall or get stuck in water

  1. Don’t try to restart a stalled engine unless the water is rising and that is your only way out. Restarting with water in the engine can destroy it.
  2. If the water is rising, leave the car and move to higher ground straight away. A car can be replaced.
  3. Don’t walk through moving water. Currents, open drains and missing road surface can all kill.
  4. If fast water traps you in the car, stay inside and call for help. If water starts rising inside the car, get onto the roof.
  5. Call for help: the Disaster Management Centre on 117, or the police on 119. Say where you are as exactly as you can.

Save those numbers in your phone now, and keep it charged.

Landslides on hill country roads

In prolonged heavy rain, check the National Building Research Organisation’s warnings before you travel through the hill country, and put the trip off if your area is under one. On the road, watch for fresh rocks or mud, cracks in the road surface, tilting trees or poles, and muddy water running down a slope. Don’t stop beneath a steep cutting, and don’t try to drive over or around a fresh slip. Turn back and report it to 117.

After driving through water

  • Drive slowly and brake gently a few times to dry the brakes.
  • Listen for new noises, and look for warning lights.
  • If water reached the cabin floor or above, or the engine stalled, don’t start the car again until a mechanic has checked it. Follow our flooded vehicle guide, and contact your insurer before arranging major repairs.

If you are buying a used car after a wet season, use the same guide’s 10-point check, and see how to choose the right vehicle for your family for the wider decision.

Quick checklist

Before the season:

  • Check tyre tread and pressure
  • Replace worn wiper blades and fill the washer bottle
  • Test all lights and the air conditioning demist
  • Pack the emergency kit
  • Confirm your flood cover in writing
  • Save 117 and 119 in your phone

Before each trip in bad weather:

  • Check the forecast and any warnings for your route
  • Decide whether the trip can wait
  • Charge your phone and allow extra time
  • Tell someone your route and when you expect to arrive

On the road:

  • Slow down, and keep at least a four-second gap
  • Use dipped headlights
  • Never drive into moving water or around a barrier
  • If you can’t see, stop somewhere safe

Sources

This guide is general safety information. In an emergency, follow the instructions of the police and disaster officials.