I should get a chance to blog in more detail in time, but for now I just wanted to share a couple of nice clues I found in the light snow and ice I walked amongst.

The first photo shows the first snow I encountered on a climb out of the Vale of Ewyas. We are looking east in this picture, the only snow to have survived the thawing warmth of the day are the thin strips hiding in the shade on the south side of the path. This technique is analogous to the one using puddles on the south side of west-east tracks.

The sunlight can be seen lighting the hillside in the background and unsurprisingly there is little snow to be found there. It is only in the shadows that it survives on the lower slopes.

On reaching the ridge and the Offa’s Dyke Path, the snow and ice were a little more abundant. In the photos below, notice how there are lines in the ice, sculpted by the wind. These lines proved consistent over the local area.

It would have been churlish not to sample some of the local bumps whilst up there and I enjoyed a fantastic walk up to High Street (named after the Roman Road that went over the peak). The conditions changed almost instantly, as they are wont to do at this time of year, from mild and sunny to bitter cold, freezing fog and ferocious winds near the summit. The map came out to check the safe descents as visibility plummeted to about 25 metres at times but the compass stayed in the rucksack: the wind was blowing hard and very constantly from the southwest so I only needed to make sure that my right cheek stayed frozen to hold my southeasterly course down. There were also some helpful pockets of lee snow tucked into the hillsides.

In the photo above you can see how the ice has not formed symmetrically around this triangulation pillar: as we look just east of south there is no ice on the neareast northern side. This may seem counerintuitive as you might expect to find more ice on the shaded northern side, but the reason for the lack of snow on the northern side here is that this ice has been caused by moisture in the air that is near or just below freezing hitting the triangulation pillar which is below zero degrees and then freezing on impact. This is the same ‘rime ice’ effect that aircraft experience on their wings in these conditions. The sides facing into the wind will ice up and the lee sides, the northern and eastern sides in this case, will remain free of ice.

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. It is possible to follow one of those shy, half-concealed paths – you know the ones that flirt with the idea of being an animal track and not a human path at all – more easily by enlisting the senses of touch and hearing at night. The difference between the crisp crunch of breaking frozen flattened grass is hard to mistake with that of the thawed longer grass on either side, even if the two may occasionally look similar.

I took some photos of the results of my moon shadow stick, together with a perfect north-south line, which I will be using on my Beginner’s Guide to Natural Navigation courses. Yes, that is a bit of a tease, but those who come on the courses part with £105 and I make sure that it includes plenty of exclusive material, not least dozens of images that cannot be seen anywhere else.

As compensation, I have posted these photos that I also took yesterday, of snow clinging in long thin strips to the southeast side of the tall beech trees.

The snow has finally begun to thaw in this freezing microclimatic corner of West Sussex, but I did manage a fair amount of stomping around in the snow over the past week. This is a picture I took in my local beech woodland a couple of days ago.

Lichens are very sensitive to their environment – moisture levels and air quality in particular – but also the surface they grow on. This means that they can be used to understand direction, but a little local knowledge and familarity with the stones and barks of your area helps greatly.

There is a rust-coloured lichen that is clearly not keen on surfaces that dry regularly and can be found on the moist sides of many trees in southern England, not least beech trees.

It is a reasonably dependable indicator of north on trees that are open to at least some drying from sunlight.

(If there are any lichenologists out there that might be able to point me to the right page of the ‘Mosses and Liverworts of Britain and Ireland Field Guide’ for this particular friend I’d be very grateful.)

We live off a road that becomes totally impassable very quickly: no ploughing, salt or grit has been seen in these parts! All journeys will be on foot for a couple of days I suspect.

Fortunately I managed to get out to my Contessa 32 yesterday and turn a heater on. I’m hoping to go sailing this weekend and if I can get to Chichester marina it may prove possible. Whilst at the marina yesterday I noticed that the northerly wind was corralling the flakes of snow that were settling on the surface down into the southern nooks of the marina. Unbelievably the southern edges of the marina appeared to have some very loose pack ice!

Here I am taking a break from family duties and checking that the snow is doing what I have come to expect of it. The compass feels very light after hours of hauling a tobogganing sled, weighed down by two lumps, up the hill repeatedly.

The woods managed to be both white and dark simultaeously.

I have just returned from three hours of exhiliration and the sharpest air to a bowl of perfect porridge. There were many treats along the way, some of them navigational, that will find their way to this space in time. Time to chain myself to a desk for several hours.

The fresh air should keep me going for a few hours, but if things slow later today then I will reach for Plan B. It is a plan that is dark and bad. I’m not much of a coffee drinker, but there is some nuclear-strength chocolate in the cupboard. The sort of thing Dr Evil would eat. It’s pure cocoa solids by another name and dissolved in hot water should do the trick.