The Machynlleth-Llanidloes Mountain Road, impassably drifted-up. The poor visibility is of note here: it is being caused by shallow advection-fog: mild moist air is moving in and is cooled by the snowfields, so that condensation occurs in its lower layers closest to the snow. This can pose a severe navigation problem to mountain-goers on occasion. Product number 2000-2009319. Email me to enquire about this image: click HERE.