Snow drifts do not really qualify as a weather phenomenon. They depend on wind and snow but occur independent of the point in time when there is snow fall. Snow drifts are caused by the direction of the wind and its strength and local conditions.

They can therefore not be predicted by the weather services. Depending on the composition of the snow, snow drifts can form when there is only a slight wind. Crusted old snow and wet snow are not suitable, fresh powder snow is.

The wind blows the light snow over to the lee side of obstacles, in other words on the side facing away from the wind. This happens in places where the snow crystals fall to the ground as a result of gravity. Snow drifts can be much higher than the height of the snow specified as a result of the precipitation and can have a height of more than 1 m, even though only 10 cm of snow have actually fallen.

Even though the height of a curb is generally enough to allow for a snow drift, one does not find the drifts very often in cities. Buildings and houses pose a resistance to the wind and the snow is deposited beforehand. But outside of city areas a curb can be high enough to provide for a small snow drift. There are a lot places in hilly and mountainous terrains where snowdrifts can accumulate. In places where the wind can blow vertically to the road there is a danger of a snow drift.

Snow drifts are a serious obstacle on streets and rails. Even if they are only a few meters wide and can still be traversed they lead to sudden changes in traffic conditions; when drivers are too fast they can result in accidents. Then there is the sidewind which can additionally hinder the stability of a street vehicle. In time one can learn how to recognize snow drifts from a distance from seeing the wind raising the snow and distributing it. The only other rule that can help serve as a protection is to only drive as fast as one can to be able to brake within one's field of vision.

Snow drifts can be prevented by erecting obstacles in such a way that the snow collects right behind the obstacle or is blown across the street. You need experience to do this. Wooden or plastic guard rails are erected in places that are particularly dangerous. Plants along the road can also be helpful in preventing snow drifts from occurring in the winter because they offer the wind enough resistance and the snow collects in front of them.