“Flash flooding is perilous and can strike unexpectedly,” the State Emergency Service (SES) cautioned in a recent post on the platform X.

On the previous day, Dean Narramore from the Bureau of Meteorology predicted “severe thunderstorms” set to impact eastern New South Wales (NSW) and southern Queensland today.

“We’re expecting widespread rain and thunderstorms across large parts of eastern New South Wales from Friday afternoon into the evening,” he detailed.

Heavy rainfall has already been observed this morning, prompting the Bureau of Meteorology to issue severe thunderstorm alerts for regions including Sydney, the Blue Mountains, the Hawkesbury, Illawarra, the Hunter, and the Central Tablelands.

In one of these warnings, the Bureau stated, “As of 8:25 am, severe thunderstorms likely to bring heavy rainfall, potentially causing flash flooding, were identified near Oakdale and Warragamba.”

The warning further specified, “These storms are projected to move towards the area west of Picton by 8:40 am and reach Camden, Picton, and the Nattai Tablelands by 8:55 am.”

Falls of 74.5mm were observed in just two hours this morning at Kangy Angy on the Central Coast, and 70mm in three hours at Lake Macquarie. 

People are urged to keep clear of creeks and storm drains, not ride or drive through floodwaters, and contact Triple Zero in emergencies.