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Altitudes, lengths, areas, maximum thicknesses and volumes of 27 glaciers that built up in a small area of the Scottish Highlands during the Loch Lomond (Younger Dryas) stadial are given. The influence of direct radiation on the glaciers is calculated taking into account transmissivity of the atmosphere, glacier aspect and surface gradient, and the albedos of ice and snow. Equilibrium firn lines for the glaciers are determined. The computed regional firn line, incorporating the influence of direct radiation had a gradient of 14.5 m/km. Former precipitation values are based on an equation for average annual mass balances of the glaciers during the stadial that incorporates glacier altitude, regional ablation gradient, direct radiation, the influence of avalanching and blowing of snow, and final glacier volume. Average July and January sea-level temperatures of 6°C and at least — 8°C, respectively, are inferred. Snowfall was principally associated with south-east winds and was similar in total to present day but rather differently distributed. Cloud amounts, at least in summer, were greater than now. A more vigorous atmospheric circulation with many depressions moving along more southerly tracks than now may have been related to the junction of polar water and North Atlantic Drift water in the immediate vicinity of the British Isles.

On Hirta, the largest island of the St. Kilda archipelago near the western edge of the Scottish continental shelf, evidence has been found for four cold periods and one intervening mild period. During the most recent cold period (the Loch Lomond Stadial), two protalus ramparts were formed. Prior to this there occurred two periods of valley glaciation separated by a mild interval during which the local vegetation was dominated by grasses and sedges. For the most recent valley glaciation (= Late Devensian glacial maximum) a mean July temperature of 4°C is inferred. At this time intensive periglacial processes were operative down to present sea level. At some earlier, pre‐Dcvensian, time St. Kilda was invaded by the Scottish ice sheet.