Great Dividing Range

The Great Dividing Range, also known as the East Australian Cordillera or the Eastern Highlands, is a cordillera system in eastern Australia consisting of an expansive collection of mountain ranges, plateaus and rolling hills. It runs roughly parallel to the east coast of Australia and forms the fifth-longest land-based mountain chain in the world, and the longest entirely within a single country. It is mainland Australia's most substantial topographic feature and serves as the definitive watershed for the river systems in eastern Australia, hence the name.

The Great Dividing Range stretches more than 3,500 kilometres (2,175 mi) from Dauan Island in the Torres Strait off the northern tip of Cape York Peninsula, running the entire length of the eastern coastline through Queensland and New South Wales, then turning west across Victoria before finally fading into the Wimmera plains as rolling hills west of the Grampians region. The width of the Range varies from about 160 km (100 mi) to over 300 km (190 mi). The Greater Blue Mountains Area, Gondwana Rainforests and Wet Tropics of Queensland World Heritage Areas are located in the Range. The highest place in Australia, the 2,228 m (7,310 ft) Mount Kosciuszko, resides in the Snowy Mountains portion of southern Great Dividing Range.

The Dividing Range does not consist of a single continuous mountain chain, but is rather a combined complex (cordillera) of mountain ranges, plateaus, hilly upland areas and escarpments with an ancient and complex geological history. The physiographic division name for the landmass is called the East Australian Cordillera. In some places the terrain is relatively flat, consisting of very low hills. Typically the highlands range from 300 to 1,600 metres (980 to 5,250 ft) in height. The mountains and plateaus, which consist of limestones, sandstone, quartzite, schists and dolomite, have been created by faulting and folding processes.

The crests of the Great Dividing Range is defined by the watershed boundary between the drainage basins of river systems east (the coastal or rainward side) and west (the inland or leeward side) of it. The higher and more rugged parts of the "range" do not necessarily form part of the crest of the range, but may be branches and offshoots from it. The term "Great Dividing Range" may refer specifically to the watershed crest of the range, or to the entire upland complex including all of the hills and mountains between the east coast of Australia and the central plains and lowlands. At some places it can be up to 400 km (249 mi) wide. Notable ranges and other features which form part of the range complex have their own distinctive names.^{[citation needed]}

As a rule of thumb, rivers east/southeast of the Dividing Range drain directly eastward into the South Pacific and the Tasman Sea, or southward into the Bass Strait. Rivers west of the Dividing Range drain in various westerly directions according to latitudes: the Murray–Darling basin in southeastern Australia (Darling Downs/eastern South West Queensland, West/Central New South Wales, Northern Victoria and the Murraylands/Riverland region of southeastern South Australia) drain southwestwards into the Great Australian Bight via the coastal Lake Alexandrina; the eastern half of the Lake Eyre basin in east central Australia (the Cooper Creek and Warburton River systems in Central/western South West Queensland and eastern Far North of South Australia) drain southwestwards into the endorheic Kati Thanda–Lake Eyre; the numerous rivers of western Cape York Peninsula in northeastern Australia (North/Far North Queensland) drain westwards or northwestwards directly into the Gulf of Carpentaria.^{[citation needed]}

The sharp rise between the coastal lowlands and the eastern uplands has affected Australia's climate, mainly due to orographic precipitation, and these areas of highest relief have revealed an impressive gorge country. Areas to the east of the mountain range in southern NSW usually experience a Föhn effect, which is a dry wind originating from the Great Dividing Range that abruptly raises the air temperature in the lee of that mountain range and reduces atmospheric moisture. This dry wind, which elevates fire danger in the warm months, occurs because of the partial orographic obstruction of relatively damp low-level air and the subsiding of drier upper-level air in leeward of the mountains. The drier air is then heated more because of the adiabatic compression as it comes down the lee slopes, forming a rain shadow.

In the cool season, the Great Dividing Range would shield much of the southeast (i.e. Sydney, Central Coast, Hunter Valley, Illawarra, the ACT, the Monaro and South Coast) from south-westerly cold fronts that originate from the Southern Ocean, which bring chilling rains, sleet and snow to the upwind side of the ranges, such as on the western Central Tablelands, South West Slopes and Snowy Mountains regions – all which have relatively wetter winters. Upwind locations include Crookwell, Batlow, Tumut, Corryong, Bright, Beechworth, Eildon, Tolmie and those in West Gippsland (namely the Latrobe Valley and Wilsons Promontory). Whereas on the downwind (eastern) slopes, Cooma, Omeo, Goulburn, Bowral, Bombala, Nimmitabel, and Canberra, are warmer and drier relative to altitude.

Moreover, Oberon, Shooters Hill and Sunny Corner are on the crest of the ranges and thus exposed from all directions, hence their evenly spread rainfall. The main ski resorts in New South Wales, such as Thredbo Village, Perisher and Charlotte Pass, lie transitionally between the leeward and windward side (the former town being more leeward and the latter more windward). Although they receive substantial precipitation from over the crest of the ranges, they lack the persistent cloud cover which characterises truly windward locations on the western face, which are; Cabramurra, Kiandra, Mount Buller, Falls Creek, Mount Hotham, Mount Buffalo and Mount Baw Baw.