Ex-Tropical Cyclone Koji Delivers Record Rainfall, Major Flooding to Queensland
Tropical Cyclone Koji, a Category 2 system on the Australian tropical cyclone intensity scale, affected northern Queensland in January 2026 before weakening to a tropical low at landfall. The cyclone formed over the Coral Sea from tropical low 12U and reached its strongest phase offshore before approaching the Queensland coast. Koji crossed between Ayr and Bowen after losing cyclone intensity, bringing damaging winds, widespread rainfall, and flooding across parts of Queensland. The system was monitored from 7 to 14 January 2026, with the most significant impacts recorded in the Mackay, Whitsunday, and Pioneer River catchment areas.
Monsoon Trough Spawns Koji as System Takes Shape Over Coral Sea
Tropical low 12U developed within a monsoon trough over the northern Coral Sea on 7 January 2026. The system moved slowly westward during its early stage before turning southward as the surrounding atmospheric pattern changed. Increasing monsoon flow from the north and stronger southeasterly winds south of the circulation helped the low develop a broader wind field.
On 9 January, gales began appearing intermittently in the southeastern quadrant of the system. During the overnight period into 10 January, the stronger winds expanded around the centre, allowing the Bureau of Meteorology to classify the system as Tropical Cyclone Koji at 10:00 AEST on 10 January, equivalent to 0000 UTC. At that time, Koji was located about 330 kilometres north-northeast of Townsville.
Koji strengthened over the Coral Sea and reached Category 2 intensity under the Australian tropical cyclone intensity scale later on 10 January. At its peak around 18:00 UTC on 10 January, the cyclone recorded a minimum central pressure of 987 hPa and maximum 10-minute sustained winds of about 100 kilometres per hour. Storm-force winds were also observed at Willis Island as the cyclone moved toward the Queensland coast.
The cyclone remained relatively short-lived, with its strongest conditions occurring offshore before weakening as it approached land. Koji’s track brought the circulation toward the coastal zone between Townsville and Bowen, where the combination of wind and tropical moisture became the main threat.
Gusts of 117 km/h Hit Whitsundays as Koji Crosses Coast Near Ayr
Koji’s strongest coastal winds were concentrated south of the centre as the cyclone approached northeastern Queensland. Hamilton Island recorded a wind gust of 117 kilometres per hour at 08:36 AEST on 11 January, while Hardy Reef also recorded strong winds during the cyclone’s approach.
Before reaching the coast, Koji’s gale area contracted significantly, and the system was downgraded to an ex-tropical cyclone. The former cyclone crossed the Queensland coast between Ayr and Bowen at around 10:00 AEST on 11 January, corresponding to 0000 UTC.
Wind impacts were mainly reported across the Mackay and Whitsunday regions. Strong gusts damaged trees and branches, caused some structural damage, and contributed to power outages. Several vessels broke moorings and sustained damage in affected marine areas.
Rainfall emerged as the primary hazard once the system moved inland. The circulation continued transporting tropical moisture across Queensland, producing heavy precipitation and increasing flood risks across affected catchments.
Pioneer River Catchment Drenched as Koji's Remnants Unleash 601 mm
Heavy rainfall associated with Koji produced significant flooding across central and northern Queensland catchments. Several locations in the Pioneer River catchment recorded more than 350 millimetres of rain in the 24 hours to 09:00 AEST on 11 January.
The highest rainfall total linked to the event was recorded at Mount William, where 601 millimetres fell during the 48 hours ending at 09:00 AEST on 12 January. The prolonged rainfall caused river levels to rise rapidly, with flooding affecting areas along the former cyclone’s inland path.
The Pioneer River basin experienced some of the most severe rainfall impacts, with saturated catchments increasing runoff and extending flood conditions beyond the immediate coastal areas. Transport disruptions and water-related hazards were reported as communities responded to rising river levels.
Storm tide impacts remained limited compared with the flooding threat. Observations near Bowen and Airlie Beach recorded peak storm tides between 0.5 and 1.0 metres, remaining below the highest astronomical tides.
Koji's Brief Lifecycle Ends as Seventh Cyclone of 2025–26 Season
Koji became the seventh tropical cyclone of the 2025–26 Australian region cyclone season. The system formed from a tropical low on 7 January, was named Tropical Cyclone Koji on 10 January, and weakened into a tropical depression as it moved inland on 11 January.
The cyclone reached its peak offshore near 19.3°S and 147.9°E, with a central pressure of 987 hPa and maximum 10-minute sustained winds of approximately 100 kilometres per hour. After land interaction, weakening continued as the circulation moved across Queensland.
The event record shows a rapid transition from tropical low development in the Coral Sea to a Category 2 cyclone, followed by coastal weakening and inland flooding impacts. Koji’s final impacts included 117-kilometre-per-hour wind gusts at Hamilton Island, rainfall exceeding 600 millimetres at Mount William, and flooding across affected Queensland catchments.