The natural Navigation: The Right Course, Naturally

It is that time of year again. The sun and Jack Frost are working together to paint the land.

In this photo of a dog-mauled football, we are looking southeast. But why does the football’s shadow appear longer than the patch of frost? Surely, since the sun is rising it should be the other way round?

Useless clue: it doesn’t have anything to do with the dog, who wisely avoids footballs until they are well defrosted.

UPDATE: The patterns of frost we see as the day wears on are shaped by more than one factor.

The areas that have received direct sunlight will of course thaw faster than those that remain in the shade.

The colour of a surface has a huge effect too. Dark earth will thaw faster in the sun than light-coloured stone.

The wind also has a big impact on any day with a light breeze or…

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Day in, day out, paths experience a different life to that of their verges.

Very often there is undergrowth on each side of a path, sheltering one side of them from the sun’s drying rays, but their exposure to and shelter from wind also sets them apart. This can be seen most clearly when snow or frost is thawing. The path will either thaw first, or, as in this picture which I took about ten days ago, they hold onto their snow for longer.

As I mention in the book, this is something that can be of value when walking at night. If the path is big, bold and broad like this one (an old Roman road) then no help is needed in following a path at night, but if you are following one of those less clearly defined snakes in the grass then all help will be welcome.…

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The recent cold snap brought by northerly winds left the first frost across the south of England. The southern side of this chimney was sheltered from the wind and this is how it may have escaped a frost. It certainly had nothing to do with any heat from the chimney, no fire had been lit in it for the week before.

The other possibility is a gap in the roof’s insulation allowing more heat from the home to escape. Judging from the second frost-free patch on the right, it looks like it might be time to crawl around in the attic. Unfortunately we are battling with cluster flies up there at the moment so it is not a fun place to be. Must be a wind shadow in both cases. Definitely.

The northerly winds were carrying high cirrus and contrails down towards the coast this morning. They have brought colder air, as forecast yesterday. This gave us our first frost of the season. The feel and even the sounds of the grass underfoot have a relationship with the direction the air is moving.