Severe thunderstorms are likely in eastern Australia today and some areas may be affected by supercells. So, what is a supercell and how can you prepare for severe storms? Thunderstorms are towering masses of cloud that form as warm moisture-laden air rises into cold, dry air above it. This rising column of air eventually falls back down towards the ground and most of the time, this sinking air flows against the storm-building updraft, causing the storm to collapse. In some cases, the sinking air (downdraft) is shifted away from the rising air (updraft) by strong upper level winds that are flowing in a different direction to winds near the ground. This 'wind shear' can also cause the updraft of the thunderstorm to rotate. When a storm's updraft starts to rotate and its downdraft is displaced, it becomes a supercell. Supercells are the rarest type of thunderstorm and the most dangerous. They can last for hours and are capable of producing giant hailstones greater than 5cm in diameter, very heavy rainfall, destructive wind gusts above 125km/h and, in some cases, tornadoes. While supercells are the most dangerous type of storm, other types of storms are also capable of threatening lives and causing damage to your property. Severe thunderstorms have already started to develop in northwest Victoria this morning and warnings are likely to be issued in other parts of eastern Australia today. The latest storm warnings are available here: http://www.weatherzone.com.au/warnings.jsp You can prepare for severe thunderstorms by: - securing loose items around your home or property - staying up to date with the latest thunderstorm warnings - maintaining an emergency pack with a battery powered torch and radio, food supplies, and a first aid kit - having a plan in place to seek shelter when necessary