Weather Wise

Snow is unusual in Britain because it occurs only

during a narrow range of atmospheric conditions. It really can be too cold to snow.

The north wind doth blow and we shall have snow, the old saying goes, but it is more accurate for some parts of the country than others. Polar maritime air often brings snow to the north of Scotland, but on its southward path over land, it cannot replenish its moisture. So much of the south can easily have a snowless north wind. Snow will only be a common result in parts such as Kent, or north Wales, or Cornwall which jut out to let the wind reach them over the sea. When a north wind does bring snow to areas in the south, it may be through its effect in cooling the moist air that has reached those parts from the south west.

Because colder air in Britain tends to be drier, the most common conditions for snow are when the ground temperature is within two degrees of zero - cold enough to freeze, but warm enough to retain moisture. Sometimes, however, very cold snow may blow over from the Continent. It appears as very fine grains of snow rather than the full-blooded snowflakes we are used to, and that is the "wrong kind of snow" that was such a bane to British Rail a few years ago. Good British snow turns quickly to slush.