Once in a lifetime storm - ...and there?s more on the way
By ROXANNE MILLAR
A ONE-in-100-year storm dumped 120mm of rain in one hour on South Tweed yesterday, cutting roads and flooding buildings.
From 5am to 9am about 150mm of rain fell upon residential areas in Banora Point and South Tweed - a record for the year.
And more of the same is expected over the next few days by the Bureau of Meteorology.
State Emergency Service workers were called out yesterday morning to divert traffic from the flooded Minjungbal Drive, Rivendell Estate and Greenway Drive areas and to help clean up minor flooding in surrounding buildings.
Gravel, dirt and bark was washed along much of the area's roadways after the flood waters subsided late in the morning.
The Daily News's office in Rivendell Estate was one of the buildings affected, with the editorial department under about 10cm of water after stormwater drains blocked.
Tweed Shire Council engineering director Mike Rayner said the piped stormwater systems had not been designed to cope with the one-in-a-100-year storm.
"The roads are designed to be a carrier for storms in excess of a one-in-five-year event," he said.
"The inundation of parts of the local road network was predictable given the nature of the extreme event that occurred."
Bureau of Meteorology forecaster David Milhouse said the massive downpour was caused by a number of weather systems combining early this morning, made worse by the Tweed's proximity to a low pressure system off Point Danger.
"It was the combination of an upper level trough and a surface trough and a weak low. The proximity of the low and upper trough enhanced the shower and storm activity," he said.
"It looks pretty extensive with big falls out to sea and I can tell you it won't be last you will see of the activity.
"There is the potential for further moderate to heavy falls, particularly late Wednesday and early Thursday morning."
The Bureau's severe storm meteorologist Peter Otto said the storm had not been rated as "severe" by their organisation.
"You have to get 60 to 70mm of rain in an hour and what our readings show is a one-in-two-year storm with 60mm in two hours," he said.
"It is possible that the rainfalls were heavier than we observed because it was very localised heavy rainfall."