Mackay, Queensland recently experienced an extraordinary rainfall event, receiving over 600mm in just six hours, surpassing the total annual rainfall of some regions. This significant rainfall, while alarming, was manageable for Mackay due to its history with infrequent floods. The discussion highlights the occurrence of similar heavy rainfall events, with one participant recalling experiencing 0.3m of rain in 24 hours and 0.5m in 72 hours, leading to significant flooding in their area. They also shared an experience in western Kentucky, where 15cm of rain fell in less than 24 hours, resulting in widespread flooding due to the region's flat topography and river confluence. The use of levees and flood walls in Kentucky was noted as a double-edged sword, as they can trap water in low-lying areas, prolonging flooding despite their intended protective function.
