Kimberley (Western Australia) - Geography

Geography

The Kimberley is an area of 423,517 square kilometres (163,521 sq mi), which is about three times the size of England or twice the size of Victoria.

The Kimberley consists of the ancient, steep-sided mountain ranges of northwestern Australia cut through with sandstone and limestone gorges and steep ridges from which the extreme monsoonal climate has removed much of the soil. The southern end of the Kimberley beyond the Dampier Peninsula is flatter with dry tropical grassland and is used for cattle ranching. In parts of the Kimberley such as the valleys of the Ord and Fitzroy Rivers in the south the soils are relatively usable cracking clays, whilst elsewhere they are lateritic Orthents. Although none of the mountains reach even 1,000 metres (3,281 ft), there is so much steep land as to make much of the region very difficult to traverse, especially during the wet season when even sealed roads are often flooded. The coast is typically steep cliffs in the north but flatter in the south., all subject to high tides.

The Kimberley has a tropical monsoon climate. The region receives about 90% of its rainfall during the short wet season, from November to April, when cyclones are common (especially around Broome) and the rivers flood. The annual rainfall is highest in the northwest, where Kalumburu and the Mitchell Plateau average 1,270 millimetres (50 in) per year, and lowest in the southeast where it is around 520 millimetres (20 in). In the dry season, from May to October, south easterly breezes bring sunny days and cool nights. Climate change since 1967 has led to large increases of as much as 250 millimetres (10 in) per year in annual rainfall over the whole region. Recent studies suggest Asian pollution and not global warming as the cause of this increased rainfall. In 1997 and 2000 the region received especially heavy rains, leading to record flooding of the Fitzroy and other rivers.

The Kimberley is one of the hottest parts of Australia, with the average annual mean temperature around 27 °C (81 °F), and with mean maximum temperatures almost always above 30 °C (86 °F) even in July and ranging in November before the rains break from 37 °C (99 °F) on the coast to 40 °C (104 °F) in the south around Halls Creek. Mean minima in July range from around 12 °C (54 °F) in the south to 16 °C (61 °F) around Kalumburu, whilst in November and December they are generally around 26 °C (79 °F).

The aboriginal people of the Kimberley recognise 6 traditional seasons based on meteorological events as well as observed events relating to fauna and flora.