Deadly storms that struck Australia’s east coast in December produced insured losses of $1.4 billion, the nation’s largest catastrophe loss of last year, analyst Perils says. 

The December 23-29 storms hit Victoria, NSW and Queensland, with a prolonged period of severe convective storm activity bringing large hail, intense winds, flash floods and tornadoes. 

Hail was a major contributor to property damage, with hailstones of up to 10cm in diameter reported, according to the global catastrophe data analyst. 

Head of Perils Asia-Pacific Darryl Pidcock says Australia had a relatively benign 2023 compared with recent years, but severe convective storms in Victoria this week “serve as a timely reminder of the industry’s exposure to this ... peril”. 

January 2020 hailstorms cost $1.89 billion, Perils says, and the October 2020 Halloween Storm in Queensland cost $1.22 billion. 

“For Australia, this event is not unusual,” Mr Pidcock said, adding that globally, 2023 was a record year for severe convective storm losses. 

December’s extreme weather was driven by a low-pressure system over southeast Australia that was blocked by a high-pressure system over the northern Tasman Sea. As the low intensified, its cold front pushed into warm and humid air masses over the east coast, forming convective storm cells and intense thunderstorms. 

The Insurance Council of Australia declared the event a catastrophe on December 29, escalating an earlier significant event declaration as the “immense scale and destructive nature of [the] storms” brought increasing claims numbers. 

Large hail, ferocious wind, falling trees, flying debris and flash floods were the main drivers of damage. There were 10 deaths, most caused by drowning or falling trees.