Storms have moved through north-western New South Wales, bringing down power poles and trees, and tearing roofs off houses overnight.
Emergency services in the area have already been dealing with dozens of bushfires, with more fires now burning as a result of lightning.
Electricity supplier Essential Energy says crews on board helicopters will assess the damage from the air this morning.
It says up to 60 power poles have been damaged and, at the height of the storm, up to 25,000 people were without power.
About 6,500 customers are still without electricity in the Narrabri, Gunnedah and Tamworth districts.
Cattle farmer Ian MacCue from Bellata, between Moree and Narrabri, has told ABC Local Radio winds of 137 kilometres per hour tore through his property overnight.
He says the damage is so widespread he is not sure where to start.
"Three of those big cement poles have just been snapped off at ground level and there are power lines hanging throughout the trees and the paddocks everywhere," he said.
"Every building on our two properties has been partially annihilated; the hay sheds, the grain sheds, all the tools and everything in the machinery shed are strewn over hundreds of hectares.
"We've got no power, of course, and we've got 2,000 head of hungry cattle we can't feed."
Acting Incident Controller with the Namoi SES, Andrew Galvin, has told ABC Local Radio his crews have been busy.
"We had 146 requests for assistance," he said.
"We've actually removed a lot of threatening trees and we've also removed trees from driveways to give them access so they can get out to work this morning.
"Today, we'll be focusing on carrying roof repairs there's been total loss of some roofs in extreme cases."
Regional General Manager with Essential Energy Matt Patterson says the weather event is one of the worst he has seen in his career.
"At the height of the storms 25,000 customers were out from Walgett to Tamworth and everywhere in between," he said.
"We will be having helicopters that are going up in the next hour to assess the damage."
Dozens of blazes are burning in the area, including the which has destroyed at least 12 properties and damaged the Siding Spring Observatory.
Lightning strikes have started fires at Gunnedah, as well as on the outskirts of Tamworth and through the Liverpool Ranges.
Inspector Steve Prior, from the Tamworth RFS, says he is concerned about the number of new fires his crews will have to tackle today.
© ABC 2013
13:04 EDT A deep low pressure trough has spread areas of rain over southern QLD and northeastern NSW, with the heaviest along the border.