Severe Tropical Cyclone Hamish was a powerful
tropical cyclone
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depen ...
that caused extensive damage to the
Great Barrier Reef
The Great Barrier Reef is the world's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...
and coastal
Queensland
)
, nickname = Sunshine State
, image_map = Queensland in Australia.svg
, map_caption = Location of Queensland in Australia
, subdivision_type = Country
, subdivision_name = Australia
, established_title = Before federation
, establishe ...
, Australia, in March 2009. The eighth
named storm
Tropical cyclones and subtropical cyclones are named by various warning centers to simplify communication between forecasters and the general public regarding forecasts, watches and warnings. The names are intended to reduce confusion in the ...
of the
2008–09 Australian region cyclone season
The 2008–09 Australian region cyclone season was a near average tropical cyclone season. It officially started on 1 November 2008, and officially ended on 30 April 2009. This season was also the first time that the BoM implemented a "tropical ...
, Hamish developed out of an
area of low pressure
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...
on 4 March near the
Cape York Peninsula
Cape York Peninsula is a large peninsula located in Far North Queensland, Australia. It is the largest unspoiled wilderness in northern Australia.Mittermeier, R.E. et al. (2002). Wilderness: Earth’s last wild places. Mexico City: Agrupació ...
. 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
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the conve ...
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
The Bureau of Meteorology (BOM or BoM) is an executive agency of the Australian Government responsible for providing weather services to Australia and surrounding areas. It was established in 1906 under the Meteorology Act, and brought together ...
(BoM), as a tropical low over the
Coral Sea. Drifting westward, the system steadily became better defined,
developing
convective
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...
banding features later that day. Situated in an area favouring
tropical cyclone
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depen ...
development, characterised by warm waters, low
wind shear
Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizont ...
and upper-level
diffluence, the low was able to quickly strengthen. On the following day, the
Joint Typhoon Warning Center
The Joint typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command in Pearl Harbor, Hawaii. The JTWC is responsible for the issuing of tropical cyclone warnings in the North-West Pacific Ocean, South P ...
(JTWC) issued a
Tropical Cyclone Formation Alert
A Tropical Cyclone Formation Alert (TCFA) is a bulletin released by the U.S. Navy-operated Joint Typhoon Warning Center in Honolulu, Hawaii or the Fleet Weather Center in Norfolk, Virginia, warning of the possibility of a tropical cyclone formin ...
as convection wrapped around the
centre of circulation and an
anticyclone
An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from ...
developed over the system, allowing for good
outflow
Outflow may refer to:
*Capital outflow, the capital leaving a particular economy
*Bipolar outflow, in astronomy, two continuous flows of gas from the poles of a star
*Outflow (hydrology), the discharge of a lake or other reservoir system
* 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
In meteorology, rapid intensification is a situation where a tropical cyclone intensifies dramatically in a short period of time. The United States National Hurricane Center defines rapid intensification as an increase in the maximum sustained wi ...
, 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
Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, we ...
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
Severe Tropical Cyclone George was one of the most powerful Australian tropical cyclones on record, attaining a minimum barometric pressure of 902 mbar ( hPa; 26.64 inHg). It was also the strongest tropical cyclone worldwide in 2007 ...
in 2007. Later that day, Hamish attained its peak intensity with winds of 215 km/h (130 mph) along with a
barometric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...
of 924
mbar
The bar is a metric unit of pressure, but not part of the International System of Units (SI). It is defined as exactly equal to 100,000 Pa (100 kPa), or slightly less than the current average atmospheric pressure on Earth at sea lev ...
(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).
![Severe Tropical Cyclone Hamish - 8 March 2009 (MODIS Terra)](https://upload.wikimedia.org/wikipedia/commons/8/8b/Severe_Tropical_Cyclone_Hamish_-_8_March_2009_%28MODIS_Terra%29.jpg)
At its peak, Hamish was a small cyclone; gale-force winds covered an area roughly wide and the
radius of outermost closed isobar
The radius of outermost closed isobar (ROCI) is one of the quantities used to determine the size of a tropical cyclone. It is determined by measuring the radii from the center of the storm to its outermost closed isobar in four quadrants, which ...
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
In meteorology, eyewall replacement cycles, also called concentric eyewall cycles, naturally occur in intense tropical cyclones, generally with winds greater than , or major hurricanes ( Category 3 or above). When tropical cyclones reach this int ...
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
![Severe Tropical Cyclone Hamish - 9 March 2009 (MODIS Aqua)](https://upload.wikimedia.org/wikipedia/commons/a/a9/Severe_Tropical_Cyclone_Hamish_-_9_March_2009_%28MODIS_Aqua%29.jpg)
Following the formation of Hamish as a tropical low on 4 March, a Cyclone Watch was issued for areas between
Cape Melville
Cape Melville is a headland on the eastern coast of the Cape York Peninsula in Australia. To its west lies Princess Charlotte Bay. It is part of the Cape Melville National Park. Cape Melville was named Stoney Cape in 1815 by Lieutenant Charles ...
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
Hayman Island is the most northerly of the Whitsunday Islands, off the coast of Central Queensland in the locality of Whitsundays in the Whitsunday Region, Queensland, Australia. The island is . It is a private island open to the public, most ...
and later to
Mackay Mackay may refer to:
*Clan Mackay, the Scottish clan from which the surname "MacKay" derives
Mackay may also refer to:
Places Australia
* Mackay Region, a local government area
** Mackay, Queensland, a city in the above region
*** Mackay Airpor ...
and
St Lawrence
Saint Lawrence or Laurence ( la, Laurentius, lit. " laurelled"; 31 December AD 225 – 10 August 258) was one of the seven deacons of the city of Rome under Pope Sixtus II who were martyred in the persecution of the Christians that the Roman ...
.
As Hamish travelled parallel to the coastline, the watches and warnings shifted towards the south, with the warnings between Cape Melville and
Cape Flattery
Cape Flattery () is the northwesternmost point of the contiguous United States. It is in Clallam County, Washington on the Olympic Peninsula, where the Strait of Juan de Fuca joins the Pacific Ocean. It is also part of the Makah Reservation, and ...
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