Residents across southeast Queensland were caught off-guard when they were hit with a deluge of rain about 300 per cent higher than forecast.
The Bureau of Meteorology predicted about 15-50mm of rain would hit parts of Brisbane on Thursday, but by 5am that number had more than doubled before 270mm fell within a few hours before noon.
BOM meteorologist Steve Hadley had earlier said about 15 to 50mm of rain was forecast for Thursday in parts of Brisbane and Caboolture on Wednesday evening.
But that almost doubled by 5am the next morning, before more than 250mm fell within six hours.
Mr Hadley initially said there was less than a 5 per cent change of heavy rainfall.
Notifications were later sent out once it was apparent flash flooding could occur in the Moreton Bay region.
“As the rainfall continued to become more intense through the morning on Thursday, we upgraded the warning to say intense rainfall and flash flooding was more likely in that specific warning area,” he said.
Morayfield Shopping Centre and nine schools were closed and thousands of homes were without power after 190mm of rain caused flash flooding in the area within six hours.
Images circulating on social media show the shopping centre inundated with floodwater.
ABC journalist Will Murray and another man Daniel Hainey helped pull a man to safety after he drove through floodwater at Morayfield.
The Queensland Fire Department have rescued several people trapped in swift water across the city over the past two days including a man who was pulled to safety seconds before his car washed away.
The dramatic rescue unfolded at Rocksberg on Thursday and was one of 14 water related incidents fire and rescue crews attended.
Another person was pulled to safety after their car became trapped in floodwater at Forest Hill about 3.45am on Friday.
The State Emergency Service (SES) has responded to almost 420 calls for help across southeast Queensland since Thursday.
More than 150 calls were made from the Moreton Bay region, which was inundated with 270mm of rain within a few hours on Thursday.
The huge amount of rain caught authorities off guard with the City of Moreton Bay advising residents sandbag stations could not be activated for safety reasons.
“Opening them now could encourage unnecessary travel and create queues during dangerous conditions,” residents were told.
Several flood warnings have been issued across southeast Queensland as severe weather continues.
BOM warned severe thunderstorms, large hailstones and heavy rainfall could lead to flash flooding near Pittsworth, west of Brisbane, on Friday.
“A slow-moving severe thunderstorms has been detected to the west of Toowoomba near Pittsworth, slowly moving to the east,” a spokesman said.
Mr Hadley said widespread thunderstorm activity was expected across the state throughout the weekend.
He said there was a low chance of thunderstorms and heavy rainfall in Brisbane and Moreton Bay on Saturday, but that would increase on Sunday and Monday.