Severe storm weather hit New South Wales on 17-18 February 2017, causing widespread power outages across Sydney and the Central Coast and grounding numerous domestic and international flights. Northern Sydney was worst hit by large hail on the second day; hailstones greater than four centimetres in diameter were reported in Hornsby, Thornleigh and Pymble, and up to nine centimetres in Annangrove. Four people were treated in relation to lightning strikes: one man at the Rouse Hill Station in the north-west of Sydney, and three women near Bowral.
The SES received over 2 700 calls, while the Rural Fire Service reported around 100 new bush and grass fires caused by lightning. The Insurance Council of Australia reported $328 million in losses following over 50 000 claims. One insurer, IAG, reported diverting additional staff to address the event, establishing specialist hail repair units and incorporating drones into property damage assessment.
The storms occurred following record maximum temperatures in the state – over four degrees greater than the February average.