Answer:
I would go with the last answer: Heat from the Great Victoria Desert.
Step-by-step explanation:
Any powerful or extremely powerful storm is created from the convergence of warm/very warm and colder systems. In the plains this convergence will form tornadoes while, over many oceanic territories, stronger winds will form a storm on a much larger and more lengthy scale. In this case, I would go with the last answer because since cool air is largely as contributing factor in ocean temperatures, heat waves from deserts would cause a convergence of these systems, creating a powerful storm that is to be expected in many parts of the world.