When the dense grey clouds roll in, the humidity increases and a stillness is apparent, Ben Beccari is ready for work.

He is one of more than 2000 storm spotters in Australia that the Bureau of Meteorology relies on to provide important information about the weather.

The 22-year-old from Mt Kembla has been in the voluntary role for more than four years. An interest in meteorology and realisation of the importance of accurate weather predictions for organisations such as the SES - of which he is also a member - prompted him to sign up.

Storm spotters, as opposed to storm chasers who follow storm fronts, are more sedate observers.

Mr Beccari's reports on storms in the Illawarra supplement the bureau's observations, allowing storm warnings to be verified, and provide information on the symptoms of storms.

The bureau requests reports when there is hail larger than a $2 coin, damaging winds 90km/h or greater, heavy rainfall or the presence of (the extremely rare) tornadoes.

The information is used to compare their forecasting expectations with what actually occurs and to log any damage to trees or property.

But in areas without sufficient radar coverage, real time warnings from spotters can lead to timely public warnings being issued.

"Being a storm spotter does not put great demands on my time," Mr Beccari said.

"If I see severe thunderstorm phenomena I'll call it in and then write what I see.

"I also keep my eye on the forecast and the bureau's website."

Storms can be dangerous, and Mr Beccari recommends people take shelter inside when one approaches. Storm chasing is a risk, he says.

"You can find yourself in a life threatening situation."