Thursday, October 11, 2012

The weight of clouds

I could watch the moving sky for hours. From the front step of my house, I see mountains stacked with cloud; hills turning gold with the fading of the summer's grasses, lit occasionally by shafts of light falling through the cloud layer. After weeks of endless rain, we are left with the enduring beauty of the clouds.

I watch clouds as though they are a story unfolding in front of me; the roiling, unpredictable patterns as they roll inland from the coast, the higher-and-higher improbability of the huge thunderheads as they rear over the distant hills. I picture the invisible currents of air which sweep them up over the mountains, gathering in size as the water within condenses into droplets of vapour. It is pure physics, this point at which the moisture content of the air becomes too much for the declining temperature gradient of the rising hills, and the water shifts from vapour to liquid. And yet, it is poetry, the slow, gentle turning of clouds as they spill over a ridge, the churning base and pluming tops of the cumulonimbus as they roll over an open landscape. No equation, no formula can predict this chance beauty.
So unique is each cloud that I hesitate to use the strict nomenclature developed by the meteorologist Luke Howard in the early 19th century. I see storm clouds swelling from the south-west and it does not matter if they are Nimbostratus praecipitatio or Nimbostratus virga; it is irrelevant to assign the strict partitioning of a Georgian naturalist's obsession to capture the world, to pin it, to command it. It is enough, for me, to watch them change shape from my front garden, defying categories, spontaneously taking form.

I recall the water cycle pictured on a poster from the wall of my geography classroom at school: the rhythmic simplicity of clouds depositing rain on patient, simple rivers, transporting it to the sea to be evaporated into clouds again. I realise now, watching clouds darkening the hills of Cumbria, that the water disperses into a myriad of other routes: into groundwater, into the tomatoes plumpening in my greenhouse, into our bodies. And I fancy that, seventy per cent water as we are, we are part of the water cycle as much as the lakes and rivers; we are rainbows and snow, clouds and oceans. I read this week that a single cumulus cloud is typically a cubic kilometre in size. The mass of the water within is around four thousand tonnes; that's enough water to sustain the bodies of four million people. It's as much rain as can fall on Cumbria in a single day.
From my porch, the clouds have taken on a new colour, bruised like raw flesh. As evening approaches, they roll back, to reveal a frontal line of cloud edged with a translucent white so bright it is colourless, like the lip of mother-of-pearl seen within a shell. The sky is darkening to a deep indigo. A single star appears between the last threads of clouds; a point of light in an ocean of grey.