Which Marine Parks are exposed to the most tropical cyclone activity?

• The Coral Sea Marine Park and Marine Parks in the North-west are exposed to the most tropical cyclone activity.

Tropical cyclones (also known as hurricanes or typhoons, depending on where you live) generate high wind and heavy seas that can damage infrastructure and injure or kill plants and animals living in our Marine Parks. For example, in 2011 severe tropical cyclone Yasi caused major damage to coral reefs in the Great Barrier Reef (read about it) and Coral Sea by breaking corals, ripping them off the reefs and burying them in sand.

In Australia, tropical cyclones are ranked from category 1 to 5 based on their intensity, with 5 being the strongest (see how the ranking schemes vary across the world). The potential destructiveness of a cyclone, however, depends also on its size (spatial extent) - bigger cyclones can generate extreme conditions over a much larger area than small cyclones (learn more).

The map above combines cyclone intensity and size to measure exposure to tropical cyclone 'activity' (for methods, see Carrigan and Puotinen 2011). It shows the average number of days each pixel was exposed to extreme conditions from a cyclone (winds of at least gale force - 17 m/s-1) across tropical Australia, based on the time period 1985 to 2015. Of the Marine Parks exposed to cyclones, activity is typically highest in the Coral Sea and the Gascoyne.

A similar analysis for the time period 1985-2009 (below) shows you that cyclone activity in generally lower across Australia compared to the NW and NE Pacific, but is similar to that of the Caribbean and the SE Indian Ocean.

Further information:

Carrigan, A. D., & Puotinen, M. L. (2011). Assessing the potential for tropical cyclone induced sea surface cooling to reduce thermal stress on the world's coral reefs. Geophysical Research Letters, 38(23).

Puotinen, M., Maynard, J. A., Beeden, R., Radford, B., & Williams, G. J. (2016). A robust operational model for predicting where tropical cyclone waves damage coral reefs. Scientific reports, 6, 26009.

For more information contact Marji Puotinen of the Australian Institute of Marine Science at M.Puotinen@aims.gov.au.