The 2016 Challenge, day 5: Killin to Fortingall (10)

As I approached the Lawers summit, my hopes of good visibility at the top were dashed as the cloud began to close in again. And I now had another problem, too. I had been using my GPS as an altimeter, taking regular readings in order to get the elevation figure and track my progress in ascent. But now, as I took a further reading, I got a low battery warning. I had no idea how many more readings I could take before the batteries failed, but I concluded I had best reserve it for emergency use only now, until such time as I could acquire some fresh batteries for it. And so I headed on up into the clouds.