How a ‘perfect storm’ of conditions led to supercell leaving trail of destruction across Australia

An intense and ‘remarkable’ weather system triggered the hailstorms that swept through Australia and left $320million worth of damage in their wake, according to the Bureau of Meteorology.  

Golf ball-sized hailstones smashed into cars and buildings on Sunday and Monday as storms hit Melbourne, Canberra, Sydney and Queensland.

As insurance companies raced to process 29,000 claims related to storm damage, BoM research scientist Dr Joshua Soderholm explained how the slow-moving system caused chaos over the course of five days.

Giant hailstones are pictured outside Parliament House in Canberra on Monday. An intense system combining hot moisture and cold air higher in the atmosphere created the storms

He said the system consisted of a low pressure surface trough and an upper-level low – which is an area of cold air high in the atmosphere – bringing with it atmospheric instability.

Beginning on Friday in Victoria before reaching Queensland on Tuesday, the system brought in hot moisture from closer to the surface which combined with the unstable air above.

‘The surface trough was drawing in moisture from the Coral Sea right down to Victoria,’ Dr Soderholm told ABC News. 

He said the perfect storm of conditions created hailstorms and supercell thunderstorms – with Canberra unlucky enough to be at the centre of one the cells.

‘We initially saw a shower and then a weak thunderstorm, then it was rapidly intensifying into this severe thunderstorm which eventually impacted Canberra,’ he said.   

It comes as the Insurance Council of Australia revealed two thirds of the claims made relating to the storm are for damage to cars.

Canberra (pictured during Monday's storm) was unlucky enough to be at the centre of one the storm cells, BoM research scientist Dr Joshua Soderholm said

Canberra (pictured during Monday’s storm) was unlucky enough to be at the centre of one the storm cells, BoM research scientist Dr Joshua Soderholm said

One video from Canberra showed hailstones smashing through the skylight of a doctors’ surgery and falling inside while other clips showed the huge projectiles cracking car windscreens. 

The ICA has declared a ‘catastrophe’, meaning claims relating to storm damage will be prioritised by insurers. 

Experts are expecting the damage figures to climb. A storm that hit Sydney in December 2018 saw about 143,000 claims lodged, worth $1.357billion. 

One video (above) from Canberra showed hailstones smashing through the skylight of a doctors' surgery

One video (above) from Canberra showed hailstones smashing through the skylight of a doctors’ surgery

Fallen trees outside a home at Caringbah in Sydney as the clean-up operation started

Fallen trees outside a home at Caringbah in Sydney as the clean-up operation started

ICA spokesman Campbell Fuller said: ‘The Insurance Council’s catastrophe declaration means those claims are prioritised by insurers, so insurers will be looking at how best to help those customers and help them as quickly as possible.’

Referring to recent bushfires which have caused more than $300million of damage, he added: ‘It is certainly a very angry summer and we’re not even midway through the disaster season yet.’

How does this hailstorm compare to others in the past? 

The extraordinary hailstorms that battered Melbourne, Canberra and southern Sydney have caused an estimated $320million worth of damage so far.

In December 2018 a hailstorm struck Sydney and the Central Coast, causing $1.3billion worth of damage. 

The biggest storm was the 1999 storm in Sydney.

The costliest natural disaster in Australia’s history caused $1.7billion worth of damage.

The hailstorm first smashed Melbourne on Sunday night, before hitting Canberra at midday and moving up through New South Wales to reach Sydney’s Sutherland shire on Monday night.

An emergency warning telling residents to move indoors was issued about 4.45pm on Sunday for Melbourne city, Caulfield, Glen Waverley, Altona, waters off Sandringham and Williamstown.

The Red Hot Summer Tour at Mornington Racecourse was cancelled amid fears of safety over hail and lightning. 

The storm then hit Canberra on Monday, as hailstones the size of golf balls rained down on Parliament House. 

A record number of calls for help were made to the ACT Emergency Services Agency.

About 1,900 calls were made between midday and 8pm on Monday, more than triple the annual average.

Buildings and hundreds of cars were damaged as hail pelted the capital in a 30-minute frenzy of wild weather before the sun reappeared.

Emergency services worked through the night to respond to roof and window damage, fallen trees and electrical hazards.

Car windscreens were obliterated at the Australian National University and Old Parliament House, while a wind gust of 117km/h was recorded at Canberra Airport.

The Commonwealth Scientific and Industrial Research Organisation (CSIRO) building was badly damaged with hail penetrating glasshouse roofs.

A car damaged by a fallen tree in the southern Sydney suburb of Caringbah after the storms

A car damaged by a fallen tree in the southern Sydney suburb of Caringbah after the storms

The storm hit Canberra on Monday as hailstones the size of golf balls rained down

The storm hit Canberra on Monday as hailstones the size of golf balls rained down

The storm damaged 65 glasshouses and wiped out years of research.

At least two people were treated by the ACT Ambulance Service for minor injuries from the storm.

The National Museum of Australia shut its doors after the storm tore external roofing, damaged shade cloths and caused leaks in corridors, the cafe and galleries.

Animals were injured during the storm, with a koel, raven, galah, cockatoo and magpie all being treated at the Canberra Referral Hospital. 

The storm reached the outskirts of Sydney on Monday night as emergency services responded to 800 calls for help. 

A clean-up is pictured underway after severe thunderstorms hit Sydney (pictured), Newcastle and Wollongong, with the NSW SES responding to more than 800 calls overnight

A clean-up is pictured underway after severe thunderstorms hit Sydney (pictured), Newcastle and Wollongong, with the NSW SES responding to more than 800 calls overnight

Stormclouds gather over Sydney Harbour on Monday night before dumping rain on the city

Stormclouds gather over Sydney Harbour on Monday night before dumping rain on the city

The storm reached the outskirts of Sydney on Monday night as emergency services responded to 800 calls for help. Pictured: A car damaged by the bad weather

The storm reached the outskirts of Sydney on Monday night as emergency services responded to 800 calls for help. Pictured: A car damaged by the bad weather

An Instagram photo shows damage to cars after the horror hailstorm struck Melbourne

An Instagram photo shows damage to cars after the horror hailstorm struck Melbourne

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