Cyclone Hamish (2009)

Severe Tropical Cyclone Hamish was a powerful tropical cyclone that caused extensive damage to the Great Barrier Reef and coastal Queensland, Australia, in March 2009. The eighth named storm of the 2008–09 Australian region cyclone season, Hamish developed out of an area of low pressure on 4 March near the Cape York Peninsula. The storm rapidly developed into a Category 1 cyclone on the Australian intensity scale the next day. On 6 March, an eye developed, and Hamish strengthened into a Category 3 cyclone. Deep convection developed around the eye, fueling further intensification, which allowed the storm to become a Category 5 tropical cyclone late on 7 March. Hamish made its closest approach to land on 8 March, but continued moving southeastward. Eventually, the cyclone weakened and turned back towards the northwest, weakening into a remnant low on 11 March, before finally dissipating on 14 March.

Meteorological history

Severe Tropical Cyclone ''Hamish'' was first identified on 4 March 2009 by the Bureau of Meteorology (BoM), as a tropical low over the Coral Sea. Drifting westward, the system steadily became better defined, developing convective banding features later that day. Situated in an area favouring tropical cyclone development, characterised by warm waters, low wind shear and upper-level diffluence, the low was able to quickly strengthen. On the following day, the Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert as convection wrapped around the centre of circulation and an anticyclone developed over the system, allowing for good outflow. Hours later, the BoM classified the low as ''Tropical Cyclone Hamish'' as the storm began to moved southward in response to a mid-level ridge situated to the east. Shortly thereafter, the JTWC also began monitoring Hamish as a tropical storm.

Not long after being classified a tropical cyclone, Hamish began to undergo rapid intensification, quickly becoming a severe tropical cyclone, a storm with winds exceeding 120 km/h (75 mph), on 6 March. Deep convection continued to develop around a well-defined low pressure centre, allowing for further strengthening. Additionally, satellite images depicted that an eye had begun developing within the storm. A steady south-easterly track was fully established by this time as the ridge to the east and a trough over central Australia prevented westward movement. Based on radar observations, the eye of Hamish was about in diameter by 7 March. Later that day, the storm further intensified into a Category 5 cyclone on the Australian intensity scale, becoming the first to do so since Cyclone George in 2007. Later that day, Hamish attained its peak intensity with winds of 215 km/h (130 mph) along with a barometric pressure of 924 mbar (hPa; ). At the same time, the JTWC assessed the storm to have nearly become a Category 5 equivalent on the Saffir–Simpson Hurricane Scale; peak one-minute sustained winds were estimated at 250 km/h (155 mph).

At its peak, Hamish was a small cyclone; gale-force winds covered an area roughly wide and the radius of outermost closed isobar was about . After maintaining Category 5 status for roughly 24 hours, Hamish began to weaken as the interaction with coastal Australia and increased wind shear took their toll. Late on 8 March, an eyewall replacement cycle had begun to take shape, allowing the storm to maintain Category 4 intensity for the following few days. By 10 March, the storm finally began to show signs of steady weakening as shear continued to increase due to an approaching trough from the west. Later that day, the storm began to slow as it moved within a region of light steering currents. Substantial loss of convection took place during this time, causing Hamish to weaken below severe tropical cyclone status by 11 March.

Convection failed to redevelop over the centre of Hamish throughout 11 March, prompting the JTWC to issue their final advisory on the system. The BoM also declared Hamish a remnant low around the same time; however, they continued to monitor the remnant system as it began to turn towards the northwest due to a ridge south of the storm. The remnants of Hamish tracked in an erratic, north-westward direction over the next few days, backtracking over where it had been days earlier. The system finally dissipated on 14 March off the coast of Australia, never having made landfall.

Preparations

Following the formation of Hamish as a tropical low on 4 March, a Cyclone Watch was issued for areas between Cape Melville and Bowen. Early the next morning, a Cyclone Warning was declared for areas between Cape Melville and Cardwell and the watch was extended to Hayman Island and later to Mackay and St Lawrence. As Hamish travelled parallel to the coastline, the watches and warnings shifted towards the south, with the warnings between Cape Melville and Cape Flattery being cancelled during the afternoon of 6 March. New Cyclone Warnings were issued for areas between Cape Flattery and Lucinda. Due to heavy rains produced by the outer bands