Southeast Qld cleans up after wild storms

Southeast Queensland is cleaning up after wild storms brought down powerlines and tore off roofs in a dramatic end to one of the state's longest heatwaves.

Flash flooding was also reported in the Lockyer Valley, while a woman was taken to hospital after being struck by lightning.

The storm rolled into the southeast on Monday afternoon, resulting in 2700 lighting strikes, wind gusts up to 95km/h and heavy rain.

Slacks Creek, in Brisbane's south, copped 80mm of rain in half and hour with 42mm falling in 10 minutes.

However, the heaviest rain was at West Bellthorpe, inland of the Sunshine Coast, where 100mm was dumped.

The Lockyer Valley bore the brunt of the storm with flash flooding in the the low lying areas of Gatton and Forrest Hill.

Roofs were torn off two buildings and several farming sheds damaged in Grantham.

"It is significant damage to property," Lockyer Valley Mayor Steve Jones told ABC radio.

The wild weather also brought down powerlines at 120 locations and 80,000 properties were blacked out during the height of the storm.

Energex says it is working to restore power to 7500 homes still without electricity, particularly around Logan, Gold Coast and Brisbane's east.

At Logan, a 44-year-old woman was taken to hospital after being struck by lighting just after 4pm Monday, the Department of Community Safety said.

The Bureau of Meteorology says temperatures quickly plummeted to the low 20s across the southeast when the storm hit, bringing relief from one of the state's longest heatwaves.

"They dropped really quickly when the storm came through," senior forecaster Brett Harrison told AAP.

The cool change was also welcome relief to firefighters battling a large bushfire on North Stradbroke Island.

About 55mm fell on the island, helping ease the fire threat.