Sydney's latest storm damage bill is expected to exceed $65 million, with widespread damage west and north-west of the city triggering a natural disaster declaration.

The storms that swept over the region on Sunday afternoon (December 9) stunned residents with their ferocity.  Lightning strikes, torrential rain and hail as big as cricket balls cut power to 13,000 homes, caused localised flooding and damaged cars as well as smashing countless windows and roof tiles.

The State Emergency Service responded to almost 3,000 calls for help from householders.  The natural disaster zone covers all the worst hit areas, including Penrith, Blacktown, Baulkham Hills and Hornsby.  NSW Premier Morris Iemma promised government assistance.