Rainfall breaks 20-year record as systems collide

Rainfall on the Gold Coast broke a 20-year record on Monday while Brisbane copped 1.5 months of rain across three days, leading to more than 300 SES requests and a major rescue operation in the Scenic Rim.

However, conditions are expected to flip to sunny skies and cold nights within days.

On Monday, the Bureau of Meteorology predicted up to 50 millimetres of rainfall on the Gold Coast, and 30 in Brisbane, but senior meteorologist Felim Hanniffy said a “two-pronged attack” hit the south-east when weather systems overlapped.

“We had a fog band coming in from the west delivering unseasonal rain to parts of western Queensland and then had a coastal trough in the south-east,” Hanniffy said.

“[We had] large uncertainties in the lead up to this event just where that coastal trough would sit.

“If it sits offshore, then it can mean a couple of millimetres [of rain], but if it sits on shore, then it can mean a couple of hundred millimetres.”

Conditions will clear from Tuesday afternoon, and include a shift to cooler nights after the insulating cloud band lifted, Hanniffy said.

“It will be like we’ve gone from February, February to May or even June,” he said.

“The air mass under the cloud band and with that drop was quite tropical … come the latter part of this week, by [Wednesday], but particularly Thursday, we’ll have temperatures in the single figures across parts of the western suburbs.”

He said while conditions would clear across the week, scattered showers in coastal parts of south-east Queensland were possible over the weekend.

Overall, fresher, cooler, and drier conditions are predicted for the region compared with Monday, when Brisbane and the Gold Coast reported record-breaking rainfall.

On the Gold Coast, the highest rainfall was recorded over Springbrook National Park, at 191 millimetres.

This was closely followed by the Gold Coast Seaway, which recorded 190 millimetres over 24 hours from Monday.

“That was its heaviest daily May rainfall since 2003,” Hanniffy said.

Rivers rapidly rose across the day, hitting moderate flooding levels at their peak, but had fallen by Tuesday.

While only the Gold Coast experienced heavy rain, Hanniffy said prolonged moderate rainfall in Brisbane on Monday delivered the heaviest daily May rainfall in three years, at about 50 millimetres in the inner-city.

In the suburbs, rainfall totals climbed as high as 80 millimetres, and over the weekend and Monday, the inner-city rainfall totalled about 90 millimetres.

“That’s well over the monthly May average of 69 millimetres for the CBD,” Hanniffy said.

The SES reported more than 320 calls from 5am on Monday, one-third of which came from the Gold Coast.

About three-quarters of requests involved taping, while 18 per cent were for help with sandbagging.

Brisbane recorded the second-highest number of calls, at 64. Nine reported 60 roads were cut off or closed on Monday evening.

Premier David Crisafulli said flash flooding caused about 50 rescues or self-evacuations across the day.

“Incidents can happen of heavy rainfall every couple of years, and even though we’re not in that [wet] season there are still challenges,” he said.

Rescue crews also worked overnight to retrieve a group of almost 50 students and teachers after they were stranded in the Mount Barney National Park.

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