Thrillseekers may be the only ones enjoying the destructive winds left by ex-tropical cyclone Alfred as authorities warn there is still dangerous weather on the horizon.

Chris Haughton had little fear of the gusty conditions as he ran out into the water at Brighton, east of Brisbane, to kite surf.

The local said Saturday’s conditions were prime for a day on the water after Alfred crossed Moreton Island as a category one then diminished to a tropical low, lingering off the coast.

But he had hoped Alfred would pack more of a punch.

“We had a storm a few months ago that felt like it had punchy or gustier winds than this cyclone, so a bit of a fizzler,” he told AAP.

“I’m a little disappointed … I’m selfish because I want really strong wind to kite.”

But other southeast Queensland residents were battered by destructive winds, with gusts more than 90km/h recorded on the Gold Coast on Saturday afternoon.

Authorities urged residents not to become complacent as the tropical low became unpredictable and might still bring more dangerous conditions.

Up to 500mm of rain could fall as the remnants of the storm move inland, reaching Dalby by midnight on Saturday and Goondiwindi on Sunday.

“These areas of heavy to intense rainfall are of the most concern over the next 24 to 48 hours,” Bureau of Meteorology’s Matt Collopy told reporters.

The massive rain band stretching across southeast Queensland might lead to life-threatening flooding in coming days, Mr Collopy warned.

Flood warnings were in place for multiple rivers including the Brisbane River.

More than 200,000 people across the southeast and northern NSW remained without power on Saturday afternoon.

Premier David Crisafulli said it was the biggest loss of power in the state’s history.

Energex crews were working tirelessly to reconnect homes but it remained a particular challenge on the Gold Coast with the strong winds.

The power outages had also cut around half of traffic lights on the Gold Coast and 16 per cent in Brisbane with Mr Crisafulli urging drivers to use common sense.

Emergency warnings were cancelled in Queensland but thousands of residents in NSW remained in limbo after evacuating over flood risks.

Fears were growing for a man missing after his car was washed away by floodwaters at Megan near Coffs Harbour.

The 61-year-old local was driving across a flooded bridge when his vehicle was washed off and he had to cling to a tree on Thursday afternoon, NSW detective chief inspector Guy Flaherty told reporters.

He urged people not to drive through floodwaters and said authorities were assessing how to get to the area to locate the man.

There has been no loss of life in Queensland but one family was lucky to have escaped injury after four people were rushed to hospital on the Gold Coast due to carbon monoxide poisoning. 

Gold Coast Acting Mayor Donna Gates said it appeared the family had been running a generator inside, sparking a warning for others to keep the devices outside.

Residents in northern NSW’s Tweed Shire Council and Bilambil Heights were told to conserve their drinking water and boil any from taps as power outages impact reservoirs.

About 180 Australian Defence Force personnel were on the ground in both states with more on standby.

Shops began to reopen on Saturday across Queensland while Brisbane and Gold Coast airports were looking to reopen on Sunday if safe to do so.

Supermarkets were reopening on a case-by-case basis in Queensland and some public transport would  resume on Sunday excluding trains across the southeast and buses on the Gold Coast.

This post was originally published on Michael West.