On 20 May 2009, an east coast low formed off the south-east Queensland coast. In combination with a strong high pressure system in the southern Tasman Sea, gale to storm force east to south-east winds affected the northern New South Wales coast. Winds of up to 130 km/h were recorded at Byron Bay. Consequently, heavy rain occurred over a large part of the north-east region during the period 19 - 23 May, with additional heavy falls on 20 – 21 May. This was the third major flood to occur in the Mid North Coast this year, compounding damage previously caused during the February and April floods.
As a result, 240 schools were closed across the region, the Tweed area was affected by a lightning strike that disabled powerlines to the north and south of the region (12,000 homes and businesses), and the Macleay River levee at Kempsey broke its banks inundating the township. Moreover, 16,000 people on the far north coast were without power overnight and up to 35,000 people were isolated by floodwaters... One fatality occurred when a person attempted to cross a flooded creek in Coffs Harbor.
The State Government declared the following regions natural disaster areas; Kempsey, Coffs Harbour, Bellingen, Nambucca, Port Macquarie-Hastings, Tweed, Byron, Ballina, Lismore, Kyogle, Richmond Valley and Clarence Valley local Government areas.
The Insurance Council of Australia estimated the 2009 damage at $48 million, with the 2011 normalised cost of $55 million.