Scientists at the hail library want stones that fell in your yard
The woman tells Mason that she doesn’t think these will work, but she has to take them because she promised the children.
“There’s some good ones in here,” he says as he examines the pile of ice in the lab, twirling it around with his bare hands before it gets too cold to touch.
A large hailstone was spared from a recent storm.Credit: Dominique Tassel
But the grandmother also gives Mason a 6-inch hailstone that will help scientists learn more about how hail forms, moves, and the damage the stones can cause.
This storm season has already triggered an Insurance Disaster notice after more than 16,000 claims were filed across more than 140 zip codes following a single storm.
Mason collected “heavy” stones of similar size but different shapes from a house.
“That’s another thing we want to understand – the variability you get in a single location.”
Hailstones are stored and recorded at the University of Queensland.Credit: Dominique Tassel
Hailstones that melt and then refreeze raise a question: How do you accurately measure something that’s melting before you can reach it?
“That’s a real problem with trying to collect. [hail] “It’s actually super, super hard to hide it,” Mason says.
Some stones may not be completely frozen when they hit the ground, and storing them means they are completely frozen.
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“No matter how much effort we put into storing them, you actually change what we’re looking at.
“So yeah, it’s complicated.”
Photographs taken immediately after impact help scientists determine how large the hail initially was.
Scientists weigh and measure hailstones, then take photographs from every angle to create 3D scans or prints.
“We take these scans, print them out, and test them in a wind tunnel to look at what the forces are on the stone from different directions,” says Mason.
This helps scientists understand the coefficient of friction on the stone, or how much resistance it encounters as it moves through the storm.
Donated hail is collected and stored in a freezer at the University of Queensland, known as the hail library.Credit: Dominique Tassel
“If we understand the drag coefficient, we can understand how fast it is falling.
“If we understand the mass and the speed at which it falls, we can determine the energy it will impart to whatever it hits.”
Once the size is recorded, the hailstone can be cut and examined. The inner layers and core will tell the story of how it was formed.
Under a project called Hail Net, the UQ team will collect hail and wind data from 10 hail-prone locations in south-east Queensland over the next seven years.
Hail and wind are examined together for the first time and what would happen if both occurred at the same time is evaluated.
Monitoring stations are located in urban, semi-rural and rural areas to assess hail damage to infrastructure, including solar panels and different types of crops.
“Even small hailstones can destroy some crops in their early stages of growth,” says Mason.
Some crops, such as pineapples and avocados, can take years to recover from damage.
The research could lead to infrastructure being more resilient to hail.
The data will also help researchers better understand the relationship between hail detected by radar in the sky and hail hitting the ground.
The researchers also aim to establish a publicly accessible website that will provide real-time information about the amount of hail measured at each station.
