On 18 November 2001, severe thunderstorms affected many parts of eastern New South Wales. Most of the impact was felt at Nelson Bay, where thunderstorms and tornadoes occurred with winds reaching up to 150 km per hour.  It was reported more than 100 buildings were damaged and several boats destroyed. Significant wind speeds were reported, including 135km/h at Mudgee, 148km/h at Nelson Bay and 150km/h at Narrabri.

Significant damage also occurred in the Lower Hunter Valley and the Sydney metropolitan regions of Penrith, Richmond and Horsley Park from strong wind gusts. Approximately 2000 homes and 200 cars were damaged and three people were killed.

Wisemans Ferry reported hail 3 cm in size. More hail similar in size occurred at Bundarra, Ben Lomond (Northern Tablelands), and in Canberra small hail fell in the northern suburbs on the afternoon on 18 November.

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