On 4 February 2011, severe thunderstorms developed over Victoria. Tropical moisture associated with Tropical Cyclone Anthony and ex Tropical Cyclone Yasi interacted with a persistent low pressure trough extending from central Australia, through Mildura and Melbourne, to north-eastern Tasmania. Extremely high humidity and strong winds were associated with the storms which delivered record daily and multi-day rainfall totals to areas of north-east and south-east Victoria.

The rain caused flash flooding in metropolitan Melbourne and prompted flood warnings for 24 rivers and creeks. On the afternoon and evening of 4 February, a damaging microburst caused damage west of Melbourne at Laverton. Wind speed strengthened from calm to 131 km per hour in six minutes causing damage to vegetation and structures within an area of approximately one square kilometre. More than 65 per cent of Victoria recorded daily rainfall totals in the 99th percentile for February in the 24 hours to 9 am on February 5. Approximately 7 per cent of the State observed the highest daily rainfall on record on the same day and 40 stations throughout Victoria recorded multi-day rainfall totals over 140 mm between 4 and 6 February.

Nursing home residents were evacuated from Mentone, Narre Warren and Werribee, whilst the Koo Wee Rup and the Alfred hospital relocated patients. Emergency relief centres were opened in Mildura, Narre Warren, Cardinia, Pakenham and Swan Hill. State wide, more than 6000 calls were made to the Victorian State Emergency Service. The Insurance Council of Australia estimated the preliminary 2011 damage at $418.6 million