Torrential Rain, a 120-Plus Year Record from Kuranda, near Cairns (Part 1)

I was born in Darwin, and raised in the Tropics, knowing the sound of monsoon rains on a tin roof – so loud, like a heard of buffalo galloping overhead. Always wondering, as I lay in bed when it would end, whether it would flood.

Caused by deep convection this is also how the Earth cools: driving energy from the Earth-ocean surface where it has accumulated to the upper atmosphere where it can be radiated to space as infra-red emissions. That is also the water cycle, and of course, water vapour is a greenhouse gas. Quite a bit was let off recently with cyclone Jasper and all the flooding.

The rainfall record for Kuranda is more than 120 year long, providing more than 4 weather cycles of information on rainfall in the catchment draining to Cairns, that recently suffered such terrible flooding. Especially the northern beaches, home to both family and friends. I phoned my sister to offer commiserations, and of course, she had to add that it was all so ‘unprecedented – the rainfall’, she added.

I thought I would wait until the rainfall totals were in before making comment. And so it is with this new year that we have the rainfall totals for Kuranda, the longest records that I know of for that catchment, for the Barron River catchment.

Kuranda is a mountain village above Cairns – beside the headwaters of the Barron River. It's known for the Kuranda Scenic Railway, which winds its way down to Cairns through tropic rainforest dotted with spectacular palm trees growing aside waterfalls that vary from a trickle to a torrent depending, of course, on the rainfall.

As the story goes 1882 was another unprecedented year of heavy rain. It cut the supply routes from the mining towns beyond the mountains to the coastal settlements including Cairns. Legendary bushman Christie Palmerston was tasked to find a reliable supply route for a railway to link the rich mining area to the sea. And so, the Kuranda railway was built opening in 1891, and with an official Australian Bureau of Meteorology rainfall record from 1896.

This record does not extend back to 1882, but we can see that 1911 is the wettest year on record with nearly 5,000 millimeters (4,921) of rain, followed by 1979 (4,657) and most recently, over this last year nearly 4,500 mm fell (4,417). It is the case that this December 2023 is the wettest December on record, but 2023 is not the wettest year on record. The heaviest rains in 1979 fell in January, and in 1911 it was in April.

It is unfortunate that there is no continuous temperature record for Kuranda, in fact temperatures have never been measured at Kuranda, at least not by the Bureau. They were measured at the Cairns post office from 1890 to 1952, and of course, this record shows cooling of maximum temperatures from 1920 to 1940, as do maximum temperature records from around the world.

Yet, curiously, climate change catastrophists and leading sceptics alike tend to deny this cooling and go on and on, variously about the one degree C increase in temperatures through the twentieth century.

They also like to claim that it is impossible to forecast rainfall, even my colleagues at the IPA. Of course, if you strip every historical temperature record of all meaningful cycles (particularly the cooling from 1920 to 1940) then reliable rainfall forecasting does become impossible.

To be continued.