A complex low-pressure system has wreaked havoc across Australia's east coast, significantly increasing flood risks as water spills from Warragamba Dam, the largest urban water supply in the country.

Following several days of heavy rainfall, Warragamba Dam is anticipated to begin a 'moderate spill' overnight into July 3, 2025, with the spill's duration and volume contingent on additional rainfall in the catchment area.

This dam is crucial, supplying 80% of Sydney's drinking water, but regulations restrict water release to prevent flooding before predicted rainfall.

Severe weather conditions have led to thousands of residents losing power, uprooted trees, and significant beach erosion, with wind gusts reaching up to 100 km/h expected to persist in northern New South Wales.

The Bureau of Meteorology has issued warnings of potential flooding in the Hawkesbury-Nepean river catchment due to the dam's spill, echoing similar incidents that occurred in May 2025 and three times in 2024.

Since the onset of this weather event on June 30, 2025, the State Emergency Service has reported over 3,400 incidents, including 10 flood rescues.

In the Jervis Bay area, several properties are under evacuation warnings due to flooding, with residents like Fay Brown in Sussex Inlet stranded by flooded roads, highlighting the recurring nature of such issues during heavy rainfall.