On 3 December 2001, severe thunderstorms hit a wide area of New South Wales with the most impact occurring in Sydney. A storm event moving at 80-100 km per hour produced a wind gust of 174 km per hour at the north western suburb of Richmond, which set a record as the highest wind gust ever recorded in mainland New South Wales.

Other significant squalls were recorded,109 km per hour at Kurnell, 102 km per hour at Hornsby and at Gunnedah (north-west slopes) wind gusts of 137 km per hour caused damage to trees and buildings. Hail estimated to be 3 cm in diameter was reported at Pymble and 2 cm in diameter was also reported at Swansea in the Hunter Valley. Two people died when a branch of a tree fell on their tent at Crosslands Reserve, Hornsby Heights, North Sydney.

The Insurance Council of Australia estimated the 2001 damage at $30 million, with the 2011 estimated normalised cost of $57 million.