Hail up to 5cm hits Millmerran as severe storms cross Darling Downs

Severe thunderstorms brought giant hail to parts of southern Queensland on Sunday, 1 November. The Bureau of Meteorology confirmed stones about 5cm wide at Millmerran on the Darling Downs and up to about 4cm at Blackbutt.

Millmerran, a farming town south-west of Toowoomba, was hit at around 3.40pm. The bureau treats hail of about 5cm as giant hail, and one of its meteorologists compared the stones to golf balls.

The bureau tracked a separate storm between Crows Nest and Kulpi, north of Toowoomba. It was moving north-east, and towns in its path were given roughly half an hour's notice. Other severe storms were building near Esk and west of Toowoomba, and were expected to reach Pittsworth, Oakey, Woomba and Kilcoy. The northern end of Lake Wivenhoe, one of Brisbane's water supply reservoirs, also lay in the path. Seven council areas were under warning.

The forecast played out close to the bureau's timing. At about 4.50pm, hailstones up to about 4cm fell at Blackbutt in the South Burnett region. Those stones were smaller than at Millmerran, but the storm remained severe and was still moving.

The warning was marked for immediate broadcast, which asks TV and radio stations to air it repeatedly. It cited the risk of giant hail, destructive winds and rainfall heavy enough to cause flash flooding.

The flood risk was heightened because the ground was already saturated. On 27 October, storms had dropped hail of almost 8cm around Brisbane, and crews had rescued people from floodwater in the Darling Downs. The upper Condomine River was later placed under a major flood warning.

Emergency services urged people never to drive, walk, play or ride through floodwater, and to stay away from storm drains and fallen power lines. People needing help with storm damage were advised to call the State Emergency Service.

By evening the situation had eased in part. At 8.12pm the bureau cancelled its severe thunderstorm warning for south-east Queensland, saying storms were no longer affecting the area from Rainbow Beach south to Stanthorpe near the New South Wales border. A broader warning remained in place for parts of the Wide Bay and Burnett district further north.

The bureau had forecast a low pressure system to bring more showers and likely storms on Monday, followed by a brief clearing on Tuesday. It said the focus would return to south-east Queensland on Tuesday afternoon, with a possible significant thunderstorm outbreak.

November is traditionally the start of thunderstorm season on Australia's east coast. The most damaging storms are often supercells, which are rotating storms that last longer than ordinary ones and give hailstones more time to grow. Some oddly shaped stones are smaller hailstones that have frozen together.