On the afternoon of Tuesday 26 November 2019, severe, fast-moving thunderstorms travelled through the Sydney region, with strong and gusty winds bringing down powerlines, as well as trees and branches that damaged homes and cars and blocked roads. The most damage occurred in Sydney’s northern suburbs. Gusts of 104 kilometres per hour (km/h) were reported at Fort Denison, closely followed by 95km/h elsewhere on Sydney Harbour and 96km/h in Holsworthy.

Earlier that day, Sydney residents had woken to a morning of smoky skies and “hazardous” air quality. Temperatures had reached a maximum of 35C when the Bureau of Meteorology issued a severe thunderstorm warning at about lunchtime, warning of large hailstones and damaging winds during the afternoon as a cold front swept the Sydney area. The short, sharp storm hit at about 1.30pm and lasted just five to ten minutes.

In northern parts of Sydney and Newcastle about 20 millimetres (mm) of rain fell in just one hour. But the storm was swift and pinpointed, with Sydney suburbs south of the harbour not seeing any rain while northern suburbs were being drenched.

The New South Wales (NSW) State Emergency Service (SES) responded to 2279 requests for assistance that afternoon and evening across Sydney and the Blue Mountains, with a further 500 requests for assistance across the remainder of the State, mainly from residents seeking help for wind damage.

Ausgrid, one of three electrical energy distributors in Sydney, reported that 65,500 homes and businesses were without power; affected suburbs included Chatswood, Frenchs Forest, Engadine, Hornsby Heights, Villawood and Bass Hill. Ausgrid reported that the thunderstorm caused the largest power outage the network had seen in recent years.

Disruption to power supplies caused by lightning strikes and strong winds also brought some train services to a standstill, including sections of the North Shore, Central Coast and Newcastle lines where buses replaced trains before power was restored. However, traffic lights were also affected by power outages and several major roads were closed by fallen trees, delaying buses and other traffic in several areas including Pymble, Gordon, Chatswood, Roseville, Willoughby and Hornsby Heights and causing chaos for commuters returning home from work later that afternoon. Trains were running again by Tuesday night.

In other parts of NSW, lightning accompanying the thunderstorms ignited several fires: by day’s end there were 110 bushfires burning across the state, up from 67 earlier that morning. It was a day of extremes for NSW: while the Sydney region suffered thunderstorms, severe fire danger conditions were declared for the Greater Hunter region due to the hot and windy conditions while snow fell in Thredbo.

The following day, Sydney’s Karonga Public School and Lindfield East Public School were closed, and parents at Davidson High School and Mimosa Public School were told to keep children at home due to clean-up operations on school grounds. In the meantime, traffic on roads in Sydney’s north continued to be disrupted by fallen trees and blacked-out traffic lights.

Joint Australian and NSW government disaster recovery funding was provided in eleven local government areas impacted by the thunderstorms for a range of measures.