Cairns Cut Off By Floodwaters

Why is it that Australia, which is dry and mostly desert, is plagued by so many floods brought about by rain ? Also Queensland sees flooding after near record rainfall

You do not need to fall back on El Niño for an explanation.

Unlike the continental USA (which is the same area as Australia), more than half of Australia can be considered desert, where the rate of evaporation exceeds the rate of rainfall. I was raised in Southern Cross which enjoyed ten inches of rainfall and one hundred inches of evaporation.

Dry hot deserts have winds which bash and smash grains of sand against each other, creating (ultimately) wind-blown clay [articles, which settle on the top-soil.

A spattering of rain helps to settle the clay particles into the top layer of soil, so we now have clay on the surface..

Rainfall easily wets this very-fine surface, and so extra rain very easily flows away. The extra rainfall cannot easily penetrate the damp clay, and so heads off somewhere else.

Of course, the area is flat, so by the time the water reaches a creek it tumbles into the water course and heads off where it will as quickly as possible.

Until that creek debouches onto another rain-soaked layer of clay, whereupon the creek widens out and floods the new clay pan.

Rain which has collected from perhaps 20,000 acres is now concentrated on as little as a thousand acres; perhaps a town site all sealed with asphalt and concrete.

Does this make sense to you?

Consider too that aerodromes are usually built on large flat areas, and where the location is low-lying, it is most easily flooded. The flooding of aerodromes retards the arrival of air-based support.

https://www.abc.net.au/news/2024-04-17/nullarbor-floodwaters-slowly-starting-to-recede/103734638

Search