When running downhill very fast, if you stop to think, then you'll fall over. That was the sensation I had when I was painting this. I think I held my breath for those 2 hours.
I'd take a slug of water every so often, stepping back to judge where I was up to, then I'd launch back in, to make a change, or to move on down the canvas.
I could see that the clouds were lit from below and slightly from behind. This was a sky in the late afternoon, early winter, with only an hour of light left in the day. It rained later that evening.
To think, those clouds don't exist any more. It's not like painting a landscape, where the hills and trees will be there tomorrow, even though the light changes and the seasons advance. With skies, I don't know. But it's different. I know one thing can't me more unique than another unique thing. But skies are. Maybe I just need more coffee.