When snow on the Berwyn begins to melt, icy meltwater tumbles down Llanrhaeadr waterfall. The suddenly swollen river dances through the village, wreathed in snowfield air that is icy cold and laced with ozone. The Rhaeadr joins the Tanat which joins the Vyrnwy which joins the Severn. And here, in a panorama below my childhood home, the flat farmland becomes submerged in vast sheets of flood-water.