 Tropical cyclones are a cause of ecological disturbance to the Great Barrier Reef. The types of damage caused by tropical cyclones to the Great Barrier Reef is varied, including fragmentation, sediment plumes, and decreasing salinity following heavy rains (Cyclone Joy). The patterns of reef damage are similarly 'patchy'. From 1910 – 1999, 170 cyclones' paths came near or through the Great Barrier Reef. Most cyclones pass through the Great Barrier Reef within a day. In general, compact corals such as Porites fare better than branching corals under cyclone conditions. The major damage caused by Tropical Cyclone Larry was to underlying reef structures, and breakage and displacement of corals, which is overall consistent with previous tropical cyclone events. Severe tropical cyclones hit the Queensland coast every 200 to 300 years; however, during the period 1969 – 1999 most cyclones in the region were very weak – category one or two on the Australian Bureau of Meteorology scale.
