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Brownie's weather: Thunderstorms 'pack extra punch' in Spring

Brownie's weather: Thunderstorms 'pack extra punch' in Spring

Thunderstorms can occur anywhere at any time in Australia, but during the warmer months of the year they pack extra punch.

Over the coming months severe thunderstorms will drop destructive hail, spark local flash flooding, and every now and then whip up a tornado.

Severe thunderstorms stand 12 kilometres, dwarfing Mount Everest and are powered by an invisible gas, water vapour.

Storms like this caused $1.5 billion in damage in less than one hour in Sydney on April 14, 1999. Massive hail bigger than cricket balls smashed thousands of roofs.

So what makes a thunderstorm tick? I spoke with severe weather expert John Belly from the Bureau of Meteorology.

“You need to have moisture which is the fuel for the thunderstorms. You need instability and that really means cold air over the top of hot air and when the atmosphere has cold air over hot air, the hot air wants to rise and the cold air wants to sink. So you’ve got those updrafts and down drafts that gives the storm momentum.”


But severe super cell storms need something else - wind shear.

“That’s winds going in different directions, high and low in the atmosphere. The reason that’s important is that it separates the updrafts and downdrafts on the storm. It stops the down draft chocking off the updraft so the storm can live a lot longer and become a lot more intense,” John said.

You find most of those storms on the eastern seaboard. In particular, a strip that stretches from Wollongong to the Sunshine coast. Violent storms that can unleash tornadoes and destructive hail. So it begs the question, does Australia have its own Tornado Alley like the USA?

According to John, ‘northeast Victoria would be as close as we would get and I wouldn’t compare it too much to the Tornado Alley in the US in that our frequency of really intense severe thunderstorms is a lot lower than it is there."


In the Yarrawonga area, the shape of the great Dividing Range favours strong wind shear a key player in tornado development over the summer months.

Did you know thunderstorm lightning claims the lives of ten Australians every year?

If you’re caught out in a storm the best place to go is inside a building.

Another really good thing to do is to get inside a car.

The metal structure will send the electricity around the outside of the car rather than inside it.

But what if you’re caught out in the open and there’s nowhere to go? Get down low, crouch and keep your feet together, until the storm passes.

And here’s a another tip, most thunderstorms occur from mid-afternoon into the evening.