Severe thunderstorms developed over central and eastern Victoria on Sunday 19 January 2020 bringing hail up to 5.5 cm in diameter to parts of south-east Melbourne, and damaging winds, heavy rainfall and flash flooding to broader areas of the state over the following few days.

The hailstones damaged cars and homes late on the Sunday afternoon in several south-eastern Melbourne suburbs, caused part of a supermarket ceiling to collapse, and brought Monash Freeway traffic to a standstill as thunderstorms and heavy rain moved across southern Victoria. Glen Iris, Warrandyte, Malvern East and Templestowe were the worst hit when the hailstorm swept through Melbourne’s eastern suburbs just after 4.00pm. Large hailstones were also reported in Malvern, North Balwyn, Camberwell and Balaclava.

By 9.00pm that evening, the State Emergency Service (SES) had received more than 1000 calls to attend building damage, more than 200 calls for fallen trees and 140 calls for flooding. SES crews remained busy throughout the night as a band of storms continued to move across the state.

On Monday, the Bureau of Meteorology issued a series of warnings for more severe weather and thunderstorms, which delivered heavy rain over many parts of Victoria that afternoon and evening. Melbourne received about a month's rain in less than 24 hours, and many road, rail and tram services in central and eastern parts of the city were affected, creating headaches for commuters heading home from work. All eastbound lanes of the Princes Highway were closed at Pakenham just after 4:00pm, and buses were brought in to replace trains on the Sandringham train line due to flooding across the tracks at North Brighton.

While the thunderstorms were occurring, fifteen bushfires were still burning across Victoria. While the rain, humidity and cooler temperatures brought welcome relief to some firefighters, fire-affected catchments in East Gippsland and Victoria’s north-east were put on flood watch. Firefighters were withdrawn from some areas due to fears strong winds and flash flooding could topple trees, create landslides and send debris onto roads in areas damaged by fire.

Fire-affected areas in Gippsland received between 20 millimetres (mm) and 60mm of rain, and up to 40mm was recorded in the state's north-east. In Brewster, west of Ballarat, a farmer reportedly received 205mm of rain overnight after losing 50 hectares of pasture to fire the previous Wednesday. Several areas around the state recorded more than 100mm of rain, including 136mm at Mount Moornapa, west of Bairnsdale.

By Monday night, the SES had received more than 1,800 requests for assistance in the previous 24 hours.

On 21 January, the Insurance Council of Australia declared the event a catastrophe, enabling the rapid assessment of storm related claims. As at 23 March 2020, the estimated cost of damage caused by storms that had struck the Australian Capital Territory and parts of VIC and New South Wales on 19 and 20 January was $1.2 billion from 107,932 lodged claims, more than 60,000 of them for damaged motor vehicles. An estimated 30 per cent (or 32,000) of the claims arose in VIC.

Following the storms, joint Australian and VIC disaster recovery funding was made available for counter disaster operations and the restoration of essential public assets in the local government areas of Boroondara, Manningham, Murrindindi and Nillumbik.