[Australia]: Cyclone Monica

[Owen]

Queensland

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Severe Tropical Cyclone Monica originated from an area of low pressure that formed early on 16 April 2006 off the coast of Papua New Guinea. The low quickly became organised, with deep convection developing over the low-pressure centre. Early the next day, the Bureau of Meteorology in Brisbane declared that the low had developed into a Category 1 cyclone on the Australian tropical cyclone scale, with winds reaching 65km/h. Upon being classified as a cyclone, the storm was given the name Monica. Monica tracked generally westward, towards Far North Queensland, in response to a low to mid-level ridge to the south.

Low wind shear and good divergence in the path of the storm allowed for continued intensification as continued westward. Late on 17 April, Monica intensified into a category 2 cyclone, with winds reaching 95km/h. By the 18 April, the Bureau of Meteorology upgraded Monica to a severe tropical cyclone, a Category 3 on the Australian scale. This followed an increase in the storm's outflow and a fluctuating central dense overcast.

Upon being declared as Tropical Cyclone Monica on 17 April, the Bureau of Meteorology issued a gale warning for areas along the eastern coast of Far North Queensland and for northern New South Wales. Several hours later, a cyclone warning was issued for north-eastern areas as the storm intensified. An estimated 1,000 people were planned to be evacuated in Far North Queensland before officials shut down major highways in the area. Ferry services in the Great Barrier Reef and flights in and out of the region were cancelled. However, no evacuations took place according to the Emergency Management Australia. An Aboriginal Community of 700, located around the mouth of the Lockhart River, were in the direct path of the storm. The chief executive officer of the community stated that they were ready for the storm, having suffered no losses from Cyclone Ingrid which impacted the same area in 2005.

During the afternoon of 19 April, the storm made landfall roughly 40km south-southeast of the Lockhart River with winds of 130km/h.

Cyclone Monica making landfall in Far North Queensland​

Shortly after making landfall, convection associated with the storm deteriorated and the outflow became fragmented. A shortwave trough to the south caused the ridge steering Monica to weaken, leading to the cyclone moving slower. After moving over land, the storm began to weaken, with the Bureau of Meteorology downgrading the storm to weaken to Category 1 cyclone. The following day, Monica moved offshore, entering the Gulf of Carpentaria. Once back over water, favourable atmospheric conditions allowed the storm to quickly intensify. Within 24-hours of moving over water, Monica re-attained severe tropical cyclone status. Following a shift in steering currents, the storm slowed significantly and turned north-westward. Steady intensification continued through 22 April as the storm remained in a region of low wind shear and favourable diffluence. Early on 22 April the Bureau of Meteorology upgraded Monica to a Category 5 severe tropical cyclone, the third of the season. By this time, a 37km wide eye had developed within the central dense overcast of the cyclone.

Little damage was recorded in Queensland, despite Cyclone Monica being a Category 3 cyclone, as the storm impacted a sparsely populated region of the Cape York Peninsula. A storm surge of 1.23m was recorded in Mossman and waves were recorded up to 4.24m in Weipa. Heavy rainfall was also associated with the storm, exceeding 400mm near where Monica made landfall. Wind gusts up to 109km/h were recorded as the storm traversed the peninsula. Officials reported about 15 percent of the structures along the Lockhart River sustained minor damage. Minor coastal flooding was also reported due to Monica. Three Torres Strait Islanders were rescued after drifting at sea in the wake of the cyclone passing through the Torres Strait, north of mainland Queensland.

Rain radar of Cyclone Monica over the Gulf of Carpentaria

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[Owen]

Northern Territory

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Cyclone Monica attained its peak intensity on 23 April near Cape Wessel with a barometric pressure 916hPa. Maximum winds were estimated at 250km/h by the Bureau of Meteorology.

On 24 April, the mid-level ridge south of Monica weakened, causing the storm to turn towards the southwest. Following this, the storm made landfall in the Northern Territory, roughly 35km west of Maningrida, as a Category 5 cyclone with winds of 250km/h. Soon after making landfall, the storm weakened extremely quickly. Most of the convective activity associated with the storm dissipated within nine hours of moving onshore. This resulted in the storm's maximum winds decreasing by 155km/h in a 12-hour span. After this rapid weakening, the storm turned sharply west moving over the town of Jabiru as a Category 2 cyclone. Within six hours of passing this town, the Bureau of Meteorology downgraded Monica to a tropical low, as the storm was no longer producing gale-force winds. The remnants of Monica persisted for several more days, tracking near Darwin on 25 April before turning south-east and accelerating over the Northern Territory. The remnants eventually dissipated on 28 April over central Australia.

Cyclone Monica making landfall in the Northern Territory at peak intensity​

Officials closed schools throughout the Northern Territory in advance of the storm on 24 April and advised people to evacuate. A 10pm curfew was also put in place to keep people off the streets during the night. Local tours in the territory were postponed or cancelled due to the storm. Several flights in and out of Darwin were also cancelled, as was the Darwin Anzac Day march. Alcan, the world's second-largest aluminium producer, warned customers of potential interruptions to supplies on contracts from its Gove refinery. Rio Tinto's Ranger Uranium Mine ceased operations on 24 April, "as a precautionary measure".

Infrared satellite loop of Cyclone Monica making landfall in the Northern Territory​

At one point, Monica was forecast to pass directly over Goulburn Island. In response, officials evacuated the island's 337 residents to shelters set up in Pine Creek. Numerous schools in the threatened region, especially in Darwin, were closed ahead of Monica's arrival. Several shelters were opened in Darwin early on 24 April in anticipation of an influx of evacuees. Stores throughout the area reported increased sales for storm supplies, with some reducing prices on specific items. The same day, the Darwin Returned and Services League of Australia cancelled all ANZAC Day services and marches in Darwin that were to be held the next day, to ensure the safety of prospective participants.

The Wessel Islands, located off the coast of the region, suffered significant damage from the storm. Mangrove trees were uprooted throughout the islands and sand dunes were destroyed. An outstation located on one of the islands was destroyed by the cyclone. The highest 24-hour rainfall from the storm was recorded near Darwin at 340mm. A storm total for the same area was recorded at 383mm, surpassing the rainfall record for the entire month of April set in 1953. Although the storm made landfall at peak intensity in Australia's Northern Territory, the impacted areas were sparsely populated. Around the region where Monica made landfall, evidence of a 5-6m storm surge was present in Junction Bay.

Wind gusts up to 148km/h felled power lines in Maningrida; 12 homes sustained damage from fallen trees in Jabiru; and extensive damage was reported in Gunbalanya. Roughly 1,000 people also lost phone service in the region. Several highways were blocked by fallen trees throughout the area. A resort in Jabiru sustained significant damage and was closed for two weeks following the storm. Insured damages to the national parks amounted to $766,000. According to the Northern Territory Insurance Office, structural damage from Cyclone Monica amounted to $4.4 million.

Destruction caused by Cyclone Monica to Maningrida's school​

The remnants of Monica produced significant rainfall over parts of the Northern Territory several days after the system weakened below cyclone status. Flash flooding was reported throughout the Adelaide River basin as up to 261mm of rain fell in a 24-hour span. On 26 April, the remnants of Monica spawned a small tornado near Channel Point; several mangrove trees were snapped and branches were thrown to nearby beaches.

Severe Tropical Cyclone Monica was the most intense tropical cyclone, in terms of maximum sustained winds (250km/h), on record to impact Australia. In contrast to the extreme intensity of the cyclone, relatively little structural damage resulted from it due to it making landfall in a sparsely populated area. No fatalities or injuries were reported to have occurred during the storm's existence.

Cyclone Monica dissipating over the Northern Territory


Destruction to large areas of trees was caused by Cyclone Monica​