Tropical Cyclone Iris

Queensland Regional Office

Track of Tropical Cyclone Iris

Iris was a long-lived tropical disturbance that performed a looping traversal of the Coral Sea during late March and early April 2018, achieving tropical cyclone intensity on two occasions with a maximum category of 2. It remained offshore throughout its lifetime and produced only minor impacts on the Australian mainland.

The tropical disturbance was first identified over the eastern Solomon Islands on March 20th, although it remained weak and erratic for several days afterward. On March 23rd, the system consolidated northwest of Vanuatu and began to intensify as it moved westward. It was named Iris by the Fiji Meteorological Service early on March 24th, however less than 24 hours later the system weakened back below tropical cyclone intensity.

The remnant tropical low was steered southwest further into the Australian area of responsibility for the next five days. Early on March 29th, the system came within 440km of Fraser Island, and beaches from Fraser Island to the Gold Coast were closed early on the Easter long weekend due to hazardous surf. The system then turned and moved rapidly northwest for a few days. By April 1st the system had slowed down again about 400km east of Cooktown. It began to drift slowly south and intensify. Although atmospheric conditions were not completely favourable for development, Iris managed to redevelop into a tropical cyclone during the early morning of April 2nd, and reached category 2 24 hours later.

The cyclone moved southeast roughly parallel to the Queensland coast while maintaining category 2 intensity for the next 2 days. It made its closest approach to the coast (roughly 180km northeast of Hayman Island in the Whitsundays) on the morning of April 4th. During this period, the automatic weather station at Hamilton Island recorded strong gales with maximum gusts of 106 km/h. On the afternoon of April 4th the system began to slowly weaken, though it still produced gusts of 118 km/h at Frederick Reef as it approached within 120km of the station.

The system finally weakened below tropical cyclone intensity for the last time on April 6th. The remnant low performed yet another turn to the north, and was steered rapidly north-northwest again into the northern Coral Sea where it gradually dissipated south of Papua New Guinea during the following week.

Extreme values during cyclone event (estimated)
Note that these values may be changed on the receipt of later information
Maximum Category: 2
Maximum sustained wind speed: 100 km/h
Maximum wind gust: 150 km/h
Lowest central pressure: 987 hPa