January 2013 Eastern Australia floods

Tropical Cyclone Oswald

Category 1 tropical cyclone (Aus scale)
Tropical storm (Saffir–Simpson scale)
Satellite image of Tropical Cyclone Oswald on 21 January as it made landfall in Queensland
Formed	17 January 2013
Dissipated	28 January 2013
Highest winds	10-minute sustained: 65 km/h (40 mph) 1-minute sustained: 85 km/h (50 mph)
Lowest pressure	991 hPa (mbar); 29.26 inHg
Fatalities	6 (1 person missing)
Damage	$2.28 billion (2013 USD)
Areas affected	Queensland, New South Wales
Part of the 2012–13 Australian region cyclone season

Tropical Cyclone Oswald in January 2013 passed over parts of Queensland and New South Wales, Australia over a number of days, causing widespread impact including severe storms, flooding, and water spouts. Coastal regions of Queensland were the most impacted with Mundubbera, Eidsvold, Gayndah and Bundaberg in the Wide Bay–Burnett hit severely. In many places the rainfall total for January set new records. Across the affected region, damage from severe weather and flooding amounted to at least A$2.4 billion (US$2.5 billion).

7,500 residents of Bundaberg and patients at the Bundaberg Hospital were evacuated. Houses were completely washed away and parts of Bundaberg's sewage network were destroyed. Cuts to transport links including damage to numerous bridges, communication interruptions, electrical blackouts and water supply problems were experienced across wide areas. Several swiftwater rescues had to be undertaken.

On 17 January, the Australian Bureau of Meteorology's Tropical Cyclone Warning Centres and the United States Joint Typhoon Warning Center (JTWC) started to monitor a tropical low that had developed within a marginal environment for further development over the Gulf of Carpentaria. Over the next two days, the cyclone slightly developed further before the system made landfall to the southwest of Borroloola early on 19 January, where the possibility for further development became stifled. By 20 January, the system completed a clockwise loop before re-emerging into the Gulf of Carpentaria. Once back over water, the system quickly organised and strengthened into Tropical Cyclone Oswald early on 21 January. At the same time, the JTWC began monitoring the system as Tropical Cyclone 11P.

Radar imagery from Mornington Island depicted a well-defined low-level circulation with defined banding features wrapping into the centre. Situated in a very moist air mass and over the warm waters of the Gulf, some intensification was expected before Oswald struck the Cape York Peninsula. Approximately 12 hours after being named, the storm made its second landfall north of Kowanyama with winds of 65 km/h (40 mph) and the final advisory was issued by the TCWC in Brisbane. Although over land, the system was able to maintain a defined circulation and gradually reorganised as it moved southwestward. By 23 January, deep convection redeveloped over the circulation and a strong monsoonal flow became established to its north. A high pressure system over New Zealand blocked the low pressure system from moving east, away from the Queensland coast, allowing the low to move slowly along the Queensland coast also causing it to stall near Rockhampton and in southern Queensland; feeding moist air from the Coral Sea into the low which resulted in a large area of convective activity with associated heavy rainfall and a low pressure trough over New South Wales allowed the low to move south into the Tasman Sea. Favourable upper-level conditions and ample moisture allowed the system to maintain its identity despite remaining over land for a prolonged period of time. By 30 January, the system had travelled more than 3,000 km (1,900 mi) and its remnants passed south of Sydney in New South Wales, emerging into the Tasman Sea.