The Northern Sydney Storm - 21 January 1991

A very severe thunderstorm moved across the northern suburbs of Sydney during the afternoon of 21 January 1991. There was extensive damage, mainly due to the strong winds accompanying the storm. Large hail was reported up to 7cm in diameter (the size of tennis balls!) and flash flooding was reported from several locations. Some areas received more than 35mm of rain in 6 minutes and more than 60mm in half an hour.

Radar loop (images at 20 min intervals) 2:28 - 5:28pm on 21 Jan 1991	MSLP weather chart 3:00pm on 21 January 1991

Areas of most severe damage stretched from the Warrawee-Turramurra area to Duffys Forest, with significant damage occurring to property in the Ku-ring-gai, Hornsby and Warringah council areas. More than 7,000 houses were damaged, 20 of them so badly that they had to be demolished. Access to and within the affected area was greatly restricted because of fallen trees and downed power lines. Power was cut to 164,000 homes.

The total insurance pay out on the storm was nearly $215 million (July 1997) although the total damage bill may have been nearly 3 times this amount.