More heavy rain is possible across Queensland's southern and central inland areas today in the wake of severe storms leading to flash flooding overnight.

Key points: Cars and a road train have been washed away, prompting swiftwater rescues

Cars and a road train have been washed away, prompting swiftwater rescues Heavy falls have been recorded in the Maranoa region

Heavy falls have been recorded in the Maranoa region The BOM says thunderstorm activity could redevelop over inland regions

Upper Amby Creek, between Roma and Mitchell in the Maranoa, recorded 246 millimetres in the 24 hours to 9:00am.

A road train with three trailers was washed off the Warrego Highway and it took rescue crews more than two hours to retrieve the driver from his cab.

On Saturday night two people were rescued after being found clinging to a tree in floodwaters at Sarina in central Queensland, where more than 100mm of rain had fallen.

Authorities said their car was washed off a crossing on West Plain Road about 7:00pm.

Swiftwater rescue crews retrieved the pair, who were treated and assessed by paramedics at the scene.

Cattle running across a flooded property at Teeswater, south of Mitchell. ( Supplied: David Todd )

Bureau of Meteorology forecaster Jonty Hall said more flooding was possible.

"The main sort of risky period through that area that has experienced that heavy rainfall is through the first half of today for that thunderstorm activity to redevelop," he said.

"So [we're] not quite out of the woods as yet, but at the moment the rainfall is a lot lighter in the area."

Mr Struss said he was particularly happy because earlier rain at Mitchell had already given them some feed.

"This on top of it will be good for us," he said.

Jacob and Will Tucker welcome the rain on their property at Forestvale, north of Mitchell. ( Supplied: Meg Tucker )

"We were feeding molasses and cottonseed and hay up until mid-January, and been doing it since September.

"But given the choice, I'd rather be flood fencing and looking at happy cows than feeding them and have them run after the truck, feeding them cottonseed and molasses," Mr Struss said.

"For those people who haven't got any feed, any rain of this context is just going to run off and take a lot of topsoil with it.

"It's those people in the cultivation country that have had the really big rain on those open paddocks — they are the ones who are going to suffer pretty badly."

Further south, moderate flood levels are being recorded at St George as floodwaters arrive from upstream, with major flood levels possible later in the week.

Grazier Rowly Walker admires a full dam on his property 80 kilometres north of Mitchell. ( Supplied: Rowland Walker )

More rain than all of 2019

A decade ago, when Amby Creek was up Phil and Shannon Crocker were engaged.

Now the Amby Creek is up again and they have three boys.

In the 24 hours to 9:00am today, they received 183mm at their Muckadilla property, east of Mitchell, which is more than all of last year's falls combined.

Heavy rain has flooded Amby Creek in the southern inland Queensland town of Muckadilla. ( Supplied: Shannon Crocker )

Ms Crocker said they were assessing the damage and would have a lot of flood fencing to do.

"We can see there's been a lot of wash here … there will be a fair bit of damage, [but] we're going to take the rain every day of the week," she said.

Ms Crocker said the rain would allow them to keep their breeding stock and plant a winter crop, which they could not do last year.

"There were a lot of people, including us, that were feeling very, very flat at the end of 2019," she said.

"We were looking down the barrel of having to sell our breeders. We'd sold all of our other cattle.

"This rain just has relieved so much stress, not just for us but for everybody else.

"We didn't get a crop last year and this moisture means that we well get a crop this year."