Northern lights illuminate the Pennine skies

Allendale, Northumberland The lights dance and shift, fading or intensifying, undulating in curtains of colour

As I open the back door, the path shows up in a rectangle of light, the gravel sparkling like golden sugar. My breath shows in pale mists that billow and dissipate in the air. The owls that called repeatedly at dusk are now silent, hunting for voles across the frozen haugh. There's the sharp smell of cold, and the river seems much louder than it does by day.

Here, in the frost hollow of the valley, it is a couple of degrees lower than the surrounding hills. Cooler air, being denser, flows down into the bowl of the land. The grasses and seedheads of the garden become outlined in hoar frost, coated in spiky crystals, the shrunken browns and greys of dying foliage enlarged into something magical.