a frost-shattered upper headwall

b abraded lower part of headwall, with slabs and chocks

c scree/talus slope 

d lochans set amid moraine ridges 

e outer terminal moraine from the small Loch Lomond Stadial glacier

f disputed "protalus rampart"

Chock marks on slabs below the Fiacaill Buttress

Talus slopes below Aladdin's Buttress

 

corrie formation

sequence of ice retreat

 

Boulders forming the low ridge of the terminal moraine on the lip of the corrie

Coire an t-Sneachda

Audio tour (1-5 Mb downloads)    Introduction  On the corrie floor   Reconstructing the glacier   Age of the moraines  Below the Fiacaill Buttress  Postglacial change  Rockfall

This is a classic example of a glacial corrie or cirque. In Gaelic, Coire an t-Sneachda is the 'corrie of the snows' and it deserves its title. The hollow is north facing and shaded from the sun. It receives large volumes of snow blown from the plateau when the winds swing to the southwest.

The long profile of the corrie is close to being logarithmic in its curvature, as the sketch below shows.

The corrie shows many typical features. The headwall (a) is a cliff. The structure of the granite controls the detail of the cliff face, with buttresses in areas of widely-spaced joints and gulleys and chimneys between, a diversity that has created many challenging climbs. This diversity also reflects glacial and periglacial activity, with intense frost-riving above the latest corrie glacier and plucking of the backwall behind the glacier. In the lower parts of the headwall (b), evidence of abrasion is seen. Here there are large, steeply inclined slabs with chock marks. The scree slope (c) has formed since the last glacier filled the back of the corrie - it continues to accumulate today, as shown by the blocks resting on late-lying snow banks and the hazard to climbers of rockfalls. The lochans (d) are ponded behind low moraines from the last glacier to occupy Coire an t-Sneachda. These moraines are 1-3 m high and composed on large granite blocks, largely derived from the headwall and carried on the surface of the glacier. Until 2014, it was thought that the last glacier to occupy the corrie was during the Loch Lomond Stadial, between 11 and 10 thousand radiocarbon years ago. Kirkbride and others have now provided dating evidence that the innermost moraines in this and neighbouring cirques date from as recently as the Little Ice Age.