II.

Land and Resources

In the north-west of the county, the heather-covered Berwyn Mountains rise to 827 m (2,713 ft). To the west are the rounded grassy slopes of Plynlimon (752 m/2,467 ft), whose summit is in Ceredigion. In the south are the Brecon Beacons, the highest mountains in south Wales, and the Black Mountains. The Brecon Beacons, which were made a National Park in 1957, are made up primarily of red sandstone, and rise in places to over 610 m (2,000 ft). They also contain a limestone area, which has the longest cave system in Great Britain, covering some 19 km (12 mi). The caves at Dan-yr-Ogof are floodlit. There are many spectacular waterfalls, the most important being at Coelbred. Radnor Forest in the east is a treeless moorland, covered with moss, heath, cotton grass, and bilberry, which rises sharply from the surrounding fertile meadows to 660 m (2,165 ft).

Fertile valleys run west to east through Powys, and are the main routes of communication with England, through Shrewsbury in Shropshire, and Hereford in Hereford and Worcester. The valley of the River Severn, known as the Vale of Powys, extends across the English border. The principal rivers of Powys, the Severn, the Wye, and the Usk, eventually flow into the Bristol Channel. Some 894 sq km (345 sq mi) of the south of Powys forms part of the Brecon Beacons National Park.

The climate of Powys varies considerably. The drier eastern valleys have an average rainfall of less than 900 mm (36 in); rainfall on the higher ground in the west is double this. February is the coldest month, with average temperatures of 5° C (41° F); in August, they average 14° C (57° F).