FREMANTLE is inhabited by a collective society of humans called the Noongar, and also by a species of living cloud-creatures (Woylie) that have great influence on the meteorological properties of the planet.  The Noongar used artificially-intelligent satellites to communicate with the Woylie, which have very limited sentience but can be trained to affect the atmosphere in many ways.  Initially this led to great prosperity on Fremantle, with rains falling just where they were needed most.  But cosmic radiation eventually caused bit-rot in the software running on the satellites, and their programming went completely haywire.  Rains became torrential, leading to massive flooding.  Lightning and powerful cyclones also became extremely prevalent.  All of the large structures on Fremantle have now been destroyed, forcing the Noongar to collectively shelter in the ruins.