Lake Eyre is in the driest desert region of central Australia. It is a large endorheic lake system, which means that the water flows in, but does not flow out. As the water evaporates, the lake dries up leaving a dry salt lake. The lake does not usually completely dry up, there is often water in small areas on the lake surface. The rate that the water dries up is per year, that is about 20 times more than the rainfall in the area.