Avoiding the perils of black ice

How to spot black-ice danger areas and what to do if you encounter them

Published: March 11, 2015, 9:45 PM
Updated: June 7, 2015, 9:46 AM

Black Ice

One of the most dangerous situations a driver can encounter is surprise. When that surprise is a total loss of traction or grip, the results are not just frightening but sometimes fatal. That's the danger of black ice!

The dictionary describes black ice as "a thin, nearly invisible coating of ice that forms on paved surfaces." It can be all but impossible to see as it blends in nicely with grey or darker surfaces.

Early and late winter are the most likely periods for encountering black ice, but it also occurs during mid-winter periods of fluctuating temperatures, around the freezing point.

It often forms at dawn or just prior to dusk, when a millimetre-thin layer of condensation is created on the road by a temperature difference between the surface and the air. It can also appear at other times of the day, however, particularly when the the road is damp and the temperature drops suddenly.

Be aware of the temperature

Black ice is most likely to occur when the air temperature is close to freezing. A temperature change of a single degree can do it.

When the sun is out, it may generate enough surface heat to keep moisture on the road in a liquid state. But when it goes behind a cloud or falls under a shadow, the resultant minor drop in temperature may be enough to convert that liquid to a solid – ice.

Be alert for shady areas

The first step is surviving an encounter with black ice is to be alert for its presence. If the road is damp and the thermometer hovering near the freezing point, look well down the road for signs of shady areas. Slow down and be wary when approaching them.

Even if the road is dry, shady areas might still be damp and contain the dreaded black ice as they haven’t been dried off by the sun.

Watch oncoming vehicles

Another indicator that you may encounter a problem is apparent moisture on oncoming vehicles. Are their wipers on? Are their drivers going slowly or seeming to display extra caution?

Those signs might be an indication of an unpleasant surprise waiting for you over the next hill or around the coming corner. That is especially the case at dawn and dusk when the sun is low on the horizon and even minor elevation changes will create shadows and corresponding black-ice spots.

If you hit black ice

If you do find yourself coming into an area of black ice, keep the steering straight, if possible, and slow down.

Lift off the accelerator smoothly. Don’t snap your foot off the gas as the sudden transfer of forces may further destabilize the situation.

If you have time to brake before hitting the ice, do so. If your vehicle has ABS (anti-lock brakes) it's OK to apply the brakes while on the ice, although it probably won't have much effect, but if not it's usually best to avoid the brakes until your tires have regained traction.

If you're in a turn

If you encounter black ice with the steering wheel turned, you will probably find that the vehicle keeps going straight ahead – and turning the steering wheel even more will do nothing to help.

It is a natural reaction, but the wrong one. Do just the opposite – straighten the steering wheel to correspond with the direction the vehicle is going. Doing so will will allow the treads of the front tires to gain grip sooner as speed comes down.

Be prepared to react

Then prepare for the secondary reaction when the front tires regain grip after crossing over a patch of black ice. If the steering wheel is turned, the front tires will suddenly have traction and snatch the vehicle violently in the direction they are turned.

That’s a good thing if you’re headed for trouble and still going too quickly to avoid it, but a bad thing if you’re not ready or have turned the wheel too much in panic.

In summary, be on the lookout for conditions that will create black ice and avoid panic and sudden movements should you encounter it.