Now that we've all experienced those first snowfalls and the subsequent driving experience, let's have a little review on driving in snow.

First of all, there are two general types of snow: dry and wet.

What we're going to refer to as dry snow usually occurs in very cold temperatures. It consists of small flakes that do not stick together, that form a powder-like surface covering that is readily penetrated by vehicles. Dry snow gets into every nook and cranny and is easily blown around. It does not stick to the windshield of a moving vehicle, but might to a stationary one when it comes into contact with the warm glass.

The biggest problem with dry snow is visibility -- the small, light, dry flakes are easily disturbed, especially by vehicles moving through it. The resultant white cloud can severely limit visibility, especially when it results in what is known as a whiteout.Traction or grip is not as much of a problem in dry snow as is the visibility issue. If dry snow is deep, it is easily displaced by the vehicle and although the surface offers little traction, the ability to get the tread of the tire down through the snow to the road surface offers some grip.

The downside is that dry snow usually occurs in very cold conditions and the road surface is likely frozen. So even if you can get the tires to contact the road surface, that grip is extremely limited.

Wet snow consists of those big, heavy flakes. Wet snow packs easily, turns to water upon contact with the windshield and into slush on the surface of the road.

For many reasons, wet snow offers a bigger challenge to motorists.

First of all, it creates an even bigger visibility hazard than dry snow because it adheres to the windshield, wipers, lights, mirrors and everything else it touches. When the temperature is even a little below freezing, it accumulates on those items and becomes an even bigger problem.

In such conditions, it is wise to stop frequently and clear the wipers and lights, which both become considerably less effective with a coating of ice.

Traction is a major issue with wet snow because it accumulates on the road, turning into slush or packing into ruts.

Quite apart from the issues of starting and stopping in these conditions is the nasty situation where you have to turn into or out of ruts or tracks left on the road by vehicles ahead. The front wheels will tend to remain in the tracks.

When it comes time to turn out of them, speed, smoothness and patience are the keys. First of all, slow down; then turn the steering wheel very gradually. Abrupt or excessive steering is the main reason drivers lose control in these conditions.

Very slight steering allows the tire tread to grip and penetrate the side of the rut. It is exactly the same problem as trying to recover from dropping wheels onto the shoulder of the road in summer -- a gradual recovery is required.

If the steering is too severe or speed too great, the tire will lose forward grip; as it slows and regains grip, it will bite laterally into the side of the rut at a severe angle.

In this age of SUVs and other all-wheel-drive vehicles, a number of motorists are driving in a fake world. Four or all-wheel drive is a major boost in getting under way. The ability to apportion power to four contact patches instead of two allows much better grip when accelerating.

But when it comes time to turn or stop, all passenger vehicles have four contact patches. It doesn't matter if you have the biggest, baddest all-wheel drive on the planet or a little front-drive economy car -- you are all equal when it comes time to turn a corner or come to a stop.

Halifax-based Richard Russell runs a driving school.