Severe Tropical Cyclone Monica

Northern Territory Regional Office

Summary | Rainfall | Observations Summary | Satellite Images | Radar Images | Impact Photos

Summary

Severe Tropical Cyclone Monica caused significant impact on the Australian coast in April 2006. It crossed the Queensland east coast south of Lockhart River as a Category 3; moved into the Northern Territory and impacted on the small islands north of the Arnhem Land coast as a Category 5; before finally making landfall on the northwest Arnhem Land coast, just 35km west of Maningrida as a Category 5 cyclone.

Monica was a small cyclone in size, but very intense, not unlike Cyclone Tracy that devastated Darwin in 1974. For this reason, communities more than 100km from Monica's path (like Nhulunbuy) were affected only slightly. Generally, large rainfall totals were experienced within 100km of Monica's path, however some of the largest totals (eg 261mm in 24 hours at Kidman Springs in the Victoria River District) occurred long after Monica made landfall, and was a weakening tropical depression overland in the Northern Territory.

Despite the widespread impact area of this cyclone, and the wind strengths experienced, there have been no reports of serious injury or death in Australia. Also, as the communities had all received good warning, much preparation, including the clearing of loose materials around the populated areas, reduced the final damage toll.

On 16 April a tropical low developed just to the east of Papua New Guinea, and began to drift southwest into the Coral Sea. It developed into a tropical cyclone on 17 April, and took a more easterly track towards the north Queensland coast. TC Monica continued to develop as it approached Queensland, and crossed the coast just to the south of Lockhart River, as a Category 3 cyclone, on the afternoon of 19 April. It crossed Cape York Peninsula into the Gulf of Carpentaria on 20 April, temporarily weakening over land, but gathered strength rapidly once over water again. It then moved slowly towards the northwest, before starting a more westward track along the northern Top End coast on 23 April. It continued to travel along the north coast, before turning to the southwest on 24 April, and crossing the coast just 35km west of Maningrida in the early evening as a Category 5 cyclone. Shortly after landfall, TC Monica began extremely rapid weakening, and by the time it passed through Jabiru only 9 hours later, it had weakened to a Category 2 cyclone. At this point the cyclone began to track in a more westward direction towards Darwin, but weakened to below cyclone intensity only 3 hours later.

The cyclone crossed Cape York Peninsula at a remote location, avoiding the local townships of Lockhart River and Coen.

Communities along the north coast of the Northern Territory were not so lucky. Widespread tree damage and moderate damage to infrastructure was reported along the Arnhem Land coast, extending as far west as the township of Jabiru. The automatic weather station at Cape Wessel suffered significant damage as the cyclone passed directly over-head as a Category 5 system. Maningrida community received substantial damage as the cyclone passed just to the north of the township, with several houses damaged by fallen trees. The uninhabited coastal crossing point, just 35km west of Maningrida, suffered severe vegetation damage, with 50%-70% of all trees felled, as well as evidence of a 5-6m storm surge zone in Junction Bay. The cyclone weakened rapidly as it moved inland, however Jabiru still experienced some damage, mostly due to fallen trees. Darwin was spared the major wrath of the cyclone, with gusty winds and rain only causing minor problems with unstable trees.

As the low tracked southwards through the Top End and Victoria River District, heavy rainfall caused major flooding in the Adelaide River catchment, as well as moderate flooding in the Daly, Katherine and Victoria River catchments.

Rainfall

The maps below show rainfall during the week ending 23 and 29 April 2006 respectively. Figure 1 shows the effects of Monica in Queensland, while Figure 2 shows the effects on the Northern Territory.

Figure 1. Rainfall during the week ending 23 April, 2006.

Figure 2. Rainfall during the week ending 29 April, 2006.

Observations Summary

109 km/h gust at Lockhart River, 3pm EST 19 April
130 km/h mean wind at Cape Wessel, 8pm CST 23 April
148 km/h gust at Maningrida, 6:40 pm CST 24 April
118 km/h gust at Jabiru, 3:02 am CST 25 April

Lowest Reported Pressure

986.0 hPa at Lockhart River
970.2 hPa at Cape Wessel
986.2 hPa at Maningrida
986.6 hPa at Jabiru Airport

Rainfall - Queensland

215 mm at Lockhart River in the 24 hours until 9am on 19 April.
239 mm at Violet Vale in the 24 hours until 9am on 20 April
282 mm at Musgrave in the 24 hours until 9am on 21 April

Rainfall - Northern Territory

190 mm at Ngayawili in the 24 hours until 9am on 25 April
340 mm at Majestic Orchids (near Darwin River Dam) in the 24 hours until 9am on 26 April
261 mm at Kidman Springs in the 24 hours until 9am on 27 April

When: 3:30 pm EST 19 April
Where: 40 km south-southeast of Lockhart River
Severity Category: 3
Estimated Maximum Wind Gusts: 200 km/h
Estimated Central Pressure: 960 hPa
Estimated Storm Surge: 3 metres
Eye Radius: 19 km
Radius of Maximum Winds: 20 km
Radius of Very Destructive Winds: 20 km
Radius of Destructive Winds: 35 km

Satellite Images

Figure 3. Queensland, 19/04/2006, 12:30pm EST. Image from MTSAT satellite.

Figure 4. Northern Territory, 24/04/2006, 3pm CST. Image from MTSAT satellite.

Radar Images

Figure 5. Weipa radar at 4pm EST on 19 April 2006.

Figure 6. Gove radar at 9:20pm CST on 23 April 2006.

Impact Photos

Click on image for larger version and description.