Rime Frost, Hoar Frost, Thaw: How to Fall into Narnia.

We have been held in the hug of a cold white fog for days now. Becalmed, anaesthetised at the white-blank windows. Like the uncertainty of sleet, fog is the weather of the moment. Shifty, unsure, blanketing, blurring, keeping us home. Out in it, we move as if in a dream. Friends materialize out of the mist, new birds are heard, but not seen. We climb above sudden vistas.

The sun pours through and the fog dissipates, revealing a magnificent rime frost. Rough ice needles have formed and thickened as super-cooled droplets have frozen on contact with everything, as the fog has drifted past. There is an almost instant freeze-thaw-freeze-thaw that the great tits chime along to, as the sun reaches places in patches. Ice tinkles and clinks down, so that we walk through a strange snowstorm under each tree.

Rinsed and relieved of their burden, the conifers give off a fresh Christmas scent. The lane is pooled with white crystals and the falling ice becomes a waterfall-roar in the wood. The liquid, dripping notes from a persistent nuthatch seems to increase the flow of ice into meltwater, like the yard tap thawing into a metal pail.

There is a heavy weather alchemy on the hill. Though walkers coming down the hill tell us the southern slope is completely green and frost free, we walk through scarves and skeins of fog, wreathing and looping like a wraith.

The grass tops and scabious seedheads are frosted and rose hips and haws are outlined in ice as if by some thick, white, magic marker.

But the kaleidoscopic effect of the freezing fog’s touch on the scrub is most mesmerising; a lesson on How to Fall into Narnia. Whisked around by a hill wind, the hawthorn & gorze have whipped an egg-white fog into a meringue brittleness, creating a blurry, hypnotic and dizzying effect with the thick rime frost. It proves impossible to focus on.

But as quick as we can marvel at it, it is shed before our very eyes. The sun sparkles and warms it so that cold needles and shards tinkle and fall like opaque glass. The fog moves off like a loosed chiffon scarf down the valley.

The hill greens behind us. But by the time we get to the bottom, the fog is beginning to roll in again. Each thorn tree on the down wears half a side of white ice-blossom and a fallen petticoat of white ice-petals beneath it, uplighting the bare branches like anti-shadows. There has been an unblossoming of cold-flowers. As we look back, a single, clear, ice-glazed goblet of a hogweed head remains, half full. Mentally, we hold it up to the light and the hill and take a long drink.