Ice crystals on slate
The final shaping of the Lochaber landscape happened over the last two million years as glaciers built up and then melted back again many times. When the climate was at its coldest, ice formed large ice caps or more extensive ice sheets that covered the country.
Glens and mountain corries were scooped out by the grinding glaciers to create arêtes, hanging valleys and U-shaped troughs. You’ll find many classic examples of glacial features in Lochaber
Glaciation also created a distinctive ragged fjord coastline which includes deep salt water lochs. The deepest freshwater loch on Britain, Loch Morar, was scraped out by a glacier. Only glacial debris now blocks off its original link with the sea.
During warmer periods (called interglacials) the ice melted, causing landslides, rock falls, and transporting large volumes of sediments in rivers of melt-water.
The last major ice sheet covered Scotland around 22,000 years ago. At this time, Lochaber would have looked like modern-day Greenland, with only the highest mountain peaks piercing the ice. Could this happen again? Yes, it could! During the last 2 million years, we’ve had a series of cold ‘glacial’ periods interspersed with shorter warmer periods. These usually last about 10,000 years and it’s now been 11,500 years since the last glaciation finished...
Some of the most remarkable evidence of the ice age can be found in Glens Roy, Gloy and Spean. Ice-dammed lakes once filled these glens, but as the climate warmed the ice dams burst, releasing torrents of water and leaving behind visible lake shore lines carved into the sides of the glens. These shore lines mark the different levels reached by the water in these natural reservoirs.
The ‘parallel roads’ so called because of their straight, road-like appearance, can best be seen in Glen Roy, where you can see three different sets of ‘roads’ along the flanks of the glen.
Before geologists unravelled the story of ice ages in Scotland, many people believed that the lines were roads built by the ancient kings of Scotland. It was only in the 19th century that the first theories about glaciers were put forward and the true origins of the 'roads' were discovered.