Saturday 10 March 2018

Flooding as draught breaks in North Queensland.

Many people have been forced to flee their homes, with some needing to be evacuated by emergency services, after flooding hit the North Queensland region of Australia this week. Several people have fallen ill with gastric conditions, possibly caused by contamination of water supplies, but there are no reports of any fatalities associated with the flooding. The worst effected area is around Ingham, Innisfail and Halifax, where around 225 homes have been inundated by waters, though the cities of Townsville and Cairns have also been hit.

Flooding in the town of Ingham in the North Queensland Region of Australia this week. Courier Mail.

North Queensland has a tropical climate, with a long dry season that lasts from mid-April to Mid-December, and a short rainy season that lasts from mid-December to mid-April, during which most areas receive around 400 mm of rain per month. However this year the area has been hit by a draught, driven by unseasonably hot weather over the Coral Sea, which leads to prevailing winds flowing from the Australian Interior out to sea rather than the other way round, with almost no rain falling in December, January and February, a weather pattern that has prevailed in several recent years. 

 Flooding near Cairns this week. Stewart McLean/Gold Coast Bulletin.

This pattern appears to have been broken by the movement of Cyclone Hola over the Coral Sea, which while remote from the Australian coast has pushed water-laden air inland, leading to over 600 mm of rainfall in the Ingahm area in three days. Flooding is a common problem following periods of severe draught, as protracted periods of dry weather can cause topsoil to dry out completely, making it vulnerable to being blown away by the wind. When rain does arrive it then falls on exposed bedrock, which is much less absorbent, triggering flash flooding as the water escapes over the surface of the ground rather than sinking into it.

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