Update, 23 March 2018
Heavy rain has now moved to the Mid-North Coast, with rain easing in the Hunter. There have been reports of flash flooding on the Mid-North Coast.
Minor flooding has peaked on the Williams River today, with minor rural impacts experienced. There is minor flooding occurring on the upper Hastings River at Kindee Bridge. Minor flooding is no longer occurring on the Paterson River.
In the Mid-North Coast area, Bowraville recorded 83 mm of rain between 22 and 23 March. Further areas of heavy rain are possible overnight Friday 23 March, but easing on Saturday.
As of 23 March, New South Wales State Emergency Service (NSW SES) had received over 2,200 calls in the State Operations Centre resulting in 1,062 emergency responses with a substantial number of these around the Maitland, Lake Macquarie and Newcastle areas and the Mid-North Coast.
NSW SES have carried out 10 flood rescues, including 8 people who had driven into floodwater.
Two other victims were rescued by helicopter on 23 March. One was a farmer stranded on a flood island, and the other a kayaker who was swept downstream. Both rescues were near Wingham with both persons safe and well, according to SES.
Original Report, 21 March 2018
The New South Wales State Emergency Service (NSW SES) in Australia has reported flash flooding in the lower Hunter and the lower Mid-North Coast areas of the state after intense rainfall.
Careys Peak is a peak in the Williams Range in the Upper Hunter region recorded 153.6 mm of rain in 24 hours to 21 March, 2018. Dungog recorded almost 70 mm of rain in just 1 hour during the morning of 21 March.
1,000 Calls for Assistance
The NSW SES said it has received “almost 1,000 calls in the State Operations Centre resulting in 374 emergency responses with a substantial number of these around the Maitland, Lake Macquarie and Newcastle areas.”
Emergency teams were called on to carry out 3 flood rescues of people trapped in vehicles. NSW SES said all persons are safe and well.
Rainfall
Australia’s Bureau of Meteorology (BoM) said the heavy rain was caused by a coastal trough that developed along central parts of the New South Wales coast, cradled between two strong high pressure systems. The air coming from these three systems is converging on central parts of the NSW coast.
BoM said that “widespread steady rain will continue to fall today and Thursday over a broad area stretching from Jervis Bay to Coffs Harbour, and over to the eastern ranges”. Many locations may see close to their monthly March rainfall fall this week.
In the 24 hour period to early 21 March (local time) Upper Chichester recorded 78mm of rain and Mount Barrington saw 70mm, with most of this falling within two to three hours.
Dungog, an area notorious for flooding, recorded 68mm in 1 hour between 4.10am and 5.10am, according to BoM.
Rivers
NSW SES said that flooding is likely along the Williams River, in particular in Dungog and Mill Dam Falls.
As of evening of 21 March (local time) the Williams river had already surpassed minor flood stage (4.90 m) at Dungog, with levels standing at 5.15 metres.
At Mill Dam Falls the river rose over 3 metres in 9 hours on 21 March. As of 20:00 it stood at 4.11 metres, still below minor flood stage (6.10) but a steep increase from the 0.70 metres level of 11:00 that day.
NSW SES said that flooding may also occur along the Paterson River at Gostwyck Bridge.
