Severe Tropical Cyclone Thelma was a

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. Depend ...

that affected northern

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

from 6 December 1998 until 12 December 1998. Cyclone Thelma was one of the most intense tropical cyclones to be observed off the coast of Australia. Thelma formed in the

Arafura Sea The Arafura Sea (or Arafuru Sea) lies west of the Pacific Ocean, overlying the continental shelf between Australia and Western New Guinea (also called Papua), which is the Indonesian part of the Island of New Guinea. Geography The Arafura Sea is ...

north of the

Northern Territory The Northern Territory (commonly abbreviated as NT; formally the Northern Territory of Australia) is an states and territories of Australia, Australian territory in the central and central northern regions of Australia. The Northern Territory ...

while intensifying rapidly into a Category 5 cyclone, passing very near the

Tiwi Islands The Tiwi Islands ( tiw, Ratuati Irara meaning "two islands") are part of the Northern Territory, Australia, to the north of Darwin adjoining the Timor Sea. They comprise Melville Island, Bathurst Island, and nine smaller uninhabited islands, wi ...

and posing a severe threat to Darwin, but passed by at a distance of . It then moved across the

Timor Sea The Timor Sea ( id, Laut Timor, pt, Mar de Timor, tet, Tasi Mane or ) is a relatively shallow sea bounded to the north by the island of Timor, to the east by the Arafura Sea, and to the south by Australia. The sea contains a number of reefs, ...

before hitting the north

Kimberley Kimberly or Kimberley may refer to: Places and historical events Australia * Kimberley (Western Australia) ** Roman Catholic Diocese of Kimberley * Kimberley Warm Springs, Tasmania * Kimberley, Tasmania a small town * County of Kimberley, a ...

coast. Thelma was the first known Category 5 cyclone to be observed in the

, and was also the most intense cyclone to threaten Darwin since

Cyclone Tracy Cyclone Tracy was a tropical cyclone that devastated the city of Darwin, Northern Territory, Australia, from 24 to 26 December 1974. The small, developing easterly storm had been observed passing clear of the city initially, but then turned t ...

on Christmas Eve in 1974. Ten months after the storm's passage, the skull of an 81-year-old man, who was believed to have been swept away by flood waters, was discovered.

Meteorological history

A developing low in the Timor Sea in early December was named Thelma at 2 p.m. Australian

Central Standard Time The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, some Caribbean Islands, and part of the Eastern Pacific Ocean. Central Standard Time (CST) is six hours behind Coordinate ...

(0430 UTC) on 6 December, located about north of Darwin. The new cyclone drifted slowly south while rapidly intensifying. Thelma's intensity increased from a Category 2 to a Category 4 during 7 December. Thelma turned towards the southwest and reached Category 5 intensity on the Australian scale just north of Bathurst Island at about 9 a.m. CST on 8 December (2330 UTC 7 December). The cyclone attained a minimum central pressure of 920

hPa HPA may refer to: Organizations * Harry Potter Alliance, a charity * Halifax Port Authority, Canada * Hamburg Port Authority, Germany * Hawaii Preparatory Academy, a school in Hawaii, US * Health Protection Agency, UK * Heerespersonalamt, the Ger ...

, and maximum wind gusts of at 8 p.m. CST (1030 UTC) on the 8 December, only two days after being named. Cyclone Thelma's rate of intensification was close to twice the average rate of most cyclones. Thelma continued moving steadily southwest at about before turning southwards, passing about from Troughton Island. The cyclone weakened to a Category 3 while crossing the

coast northwest of

Kuri Bay Kuri Bay is a remote coastal bay in the far north of Western Australia in the Kimberley region, about north of Broome. It is a designated point on the Western Australian Forecast Areas, utilised by the Bureau of Meteorology as a boundary for ...

early on 11 December. The cyclone weakened rapidly while over land. Thelma was downgraded below cyclone strength late on 11 December while moving in a more southerly track. The ex-cyclone moved through the west Kimberley and

Pilbara The Pilbara () is a large, dry, thinly populated region in the north of Western Australia. It is known for its Aboriginal peoples; its ancient landscapes; the red earth; and its vast mineral deposits, in particular iron ore. It is also a glo ...

on 12 December and 13 December. On the morning of 14 December, the low crossed the Pilbara coast north of

Wallal Wallal is the location of a bore in the Kimberley region of Western Australia. The bore is located from the Great Northern Highway between Port Hedland and Broome and has an elevation of . The nearest town is Marble Bar, south of the bore. ...

, east northeast of

Port Hedland A port is a maritime facility comprising one or more wharves or loading areas, where ships load and discharge cargo and passengers. Although usually situated on a sea coast or estuary, ports can also be found far inland, such as Ham ...

. It then moved southward through Pilbara and dissipated.

Preparations

All residents of major communities, including Darwin, and offshore installations directly affected by the cyclone were either evacuated or were sheltered in secure accommodation. The port of Darwin was closed during the cyclone, schools were closed for one day and public cyclone shelters were opened on the night of 8 December for people who felt insecure in their place of residence. Emergency officials evacuated about 120 people in the tiny community of Kalumburu, but about 180 people were left behind. Most of those sheltered in an old monastery which had thick stone walls.

Impact

Overall, the damage caused by Cyclone Thelma was relatively light, compared with the cyclone's severe intensity. However, Thelma still had a significant impact on people's activities near the

and the Kimberley coast. In the

, the most significant impact was disruption to communications and power supplies. The telephone service throughout the Tiwi Islands was shut down for over 24 hours. The radio and television reception was interrupted by heavy rain and lightning, and the power supply in Pirlangimpi (Garden Point) was cut by fallen trees. Around Bathurst Island and northwest Melville Island, there was extensive damage to vegetation in exposed areas. Minor

coastal erosion Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward ...

occurred in Milikapiti, where waves rose up to above water level. In Pirlangimpi, many large trees were uprooted and several houses were slightly damaged. In Nguiu, Bathurst Island Township, some trees were blown down but there was no significant damage. In Darwin, there was minor damage to houses and minor disruption to power supplies, caused by falling trees. A record of rain was recorded within 24 hours at Howard Springs, and a 48-hour total of was recorded at Darwin Airport from 8 December to 10 December. The rain caused local flooding in the rural areas around Darwin, blocking off some areas. In the

Kimberley region The Kimberley is the northernmost of the nine regions of Western Australia. It is bordered on the west by the Indian Ocean, on the north by the Timor Sea, on the south by the Great Sandy Desert, Great Sandy and Tanami Desert, Tanami deserts ...

, there was minor damage to some buildings at Kalumburu and water level in the river rose to within of the town. The BHP facilities at Troughton Island were affected by very destructive winds and heavy rainfall from the cyclone's core, damaging the runway and buildings. Average wind speeds of and a maximum gust of were recorded before communications were lost. Only minor damage was received at the pearling facilities at Vansittart Bay and Kuri Bay, mainly to floating pontoons. A number of places reported daily rainfall totals in excess of including in Kalumburu on 11 December, and in Ellendake on 13 December. McGowan Island, to the north of Kalumburu received of rain between 9 December and 13 December. Parts of east Pilbara also reported heavy rains over several days.

Marble Bar Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble is typically not foliated (layered), although there are exceptions. In geology, the term ''marble'' refers to metamorphosed ...

recorded and

Newman Newman is a surname of English origin and may refer to many people: The surname Newman is widespread in the core Anglosphere. A *Abram Newman (1736–1799), British grocer *Adrian Newman (disambiguation), multiple people *Al Newman (born 1960) ...

recorded in a two-day period.

Retirement

The name Thelma was removed from the official

list of tropical cyclone names 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 ...

set out by the Tropical Cyclone Warning Centre in Darwin. It was replaced with the name Tasha, which was used for the first and only time in

2010 File:2010 Events Collage New.png, From top left, clockwise: The 2010 Chile earthquake was one of the strongest recorded in history; The Eruption of Eyjafjallajökull in Iceland disrupts air travel in Europe; A scene from the opening ceremony of ...

References

External links

Report of Thelma from Bureau of Meteorology

Track of Thelma from Australian Severe Weather

Track of Thelma from Unisys
{{DEFAULTSORT:Thelma (1998) 1998–99 Australian region cyclone season Tropical cyclones in the Northern Territory

Cyclone Thelma Severe Tropical Cyclone Thelma was a tropical cyclone that affected northern Australia from 6 December 1998 until 12 December 1998. Cyclone Thelma was one of the most intense tropical cyclones to be observed off the coast of Australia. Thelma f ...