Hall measuring up to six centimetres hit towns in the Sunshine Coast hinterland in the early hours of Thursday.
"We've got a number of activities and jobs and requests for assistance, particularly this morning in the Beerwah and Landsborough areas," QFES Deputy Commissioner Mike Wassing told the Nine Network.
"They had a significant storm, large hail.
"We've got an enormous amount of trees down, because obviously the ground is saturated, and we know we've got a number of houses impacted in that area."
A second storm was moving through the area around 6.30am, bringing wind gusts of up to 90km per hour.
A trough is moving across the southeast raising concerns about the potential for more flash flooding and renewed river rises.
Isolated areas could receive falls of more than 150 millimetres, the Bureau of Meteorology warned.
"There is some concern about these very dangerous thunderstorms so we are not over this yet, we're not out of the woods," Premier Annastacia Palaszczuk said on Wednesday.
Meanwhile, Brisbane is getting ready to mobilise Mud Army 2.0 to clean up the city which was deluged with floodwaters earlier this week.
More than 10,000 people have already registered to help and the army will officially join the battle to clean up from Thursday, Brisbane City Council said.
Nine people have already died and thousands of homes and businesses have been ruined after a massive trough dropped more than a metre of rain on many parts of the state's southeast since the start of the week.
Police are still searching for an elderly man who fell from a boat into the swollen Brisbane River near Breakfast Creek on Saturday afternoon.
In Brisbane, the river has dropped to minor-to-moderate flood levels as 8000 people sign up to the 'mud army' to help with the clean-up.
More than 17,500 homes and businesses in Brisbane, Gympie, Ipswich and Logan are believed to have been damaged by the widespread flooding, along with roads, bridges and other infrastructure.
