Hailstorm Frequency: New Study Shows 'Hail-Prone Days' Increased by 40% in Heavily Populated Areas in Australia

Hailstorm frequency has drastically changed in Australia over the past decades, indicating that although hail hazard frequency has decreased in some Australian regions, "hail-prone days" have spiked in several heavily populated areas.

This is according to a new study which asserts that how and why such change occurred remains unknown, adding that hail events in the long-term future are challenging to predict but advocates the need for resilience against the small ball-sized ice.

Just like rain and snow, hail is a form of precipitation and is known as 'pellets of frozen rain' that fall from cumulonimbus clouds as hail showers or hailstorms. In the past, hailstones have caused not only disruption and damage but can also be life-threatening, according to experts, who often advise people caught outdoors by hail to seek shelter indoors.

Now, recent research about accurately predicting the occurrence of hail events is significant when it comes to security.

Hailstorm Frequency

In the study published on the journal Climate and Atmospheric Science on September 19, researchers conducted a continental-scale analysis about changes in hail hazard in Australia. This is in the context of hail damage being the leading cause of insured losses in the country. However, this aspect has not been significantly quantified.

Since hail is a meteorological hazard in Australia, the study reported that single hail events in the country result in incurred losses of more than $1 billion AUD. The research team says that Australian cities like Brisbane, Canberra, and Sydney have all been affected by extreme hailstorm events. In this case, the team focused both on past and future hailstorm probability across the country.

Hail-Prone Days

Based on atmospheric pattern analysis, collected data shows that annual "hail-prone days" from 1979 to 2021 decreased for most parts of Australia but it increased in some heavily populated areas. For instance, the researchers found that annual hail-prone days have increased by 40% around Sydney and Perth, which are the largest cities on both Australia's east and west coasts.

The study was conducted by scientists from the University of New South Wales and the Bureau of Meteorology, who explained that a "hail-prone day" is any day of the year when the atmosphere of a particular area or region has all the required meteorological ingredients for the formation of a hailstorm.

1999 Sydney Hailstorm

In previous decades, Australia has experienced one of the world's worst hailstorm events, resulting in property damage and widespread disruption.

In April 1999, the largest hailstorm disaster in Australia occurred and has been considered the country's most expensive insured natural disaster in recorded history, an event called the 1999 Sydney hailstorm.

Experts estimated that the hail precipitation during that time weighed approximately 500,000 tons, affecting 100,000 people, and killing one person, as well as injuring several others. The hailstorm also damaged 24,000 homes, 60 schools, 23 aircraft, and 70,000 vehicles.