What is a tornado?

WHAT IS A TORNADO?

A violently rotating column of air, in contact with the ground, often visible as a funnel-shaped cloud.

Rare in Australia but can happen with almost any severe thunderstorm.

HOW COMMON?

Between 10 and 20 are sighted in Australia every year.

160 in Victoria since 1918.

HOW DO THEY FORM?

Need intense, sustained updraught.

Strong change in wind speed and/or direction.

Strong winds at cloud-top level.

WHERE DO THEY FORM?

Mostly near the back of a thunderstorm, usually to the west.

WHAT'S IT LIKE?

Heavy rain and hail first.

A violent wind lasting from several seconds to two minutes as it passes.

While you can hear sounds caused by damage, many tornadoes are silent.

After storm, some light rain or hail can occur, along with cooler winds.

TYPES OF TORNADOES

Weak tornadoes are most likely during mid-summer thunderstorms, but can occur during winter months in southern Australia

Strong tornadoes typically happen with late spring/early summer

HOW FAST DO THEY MOVE?

Tornadoes travel with a thunderstorm cloud at about the same speed and direction - around 30-50km/h.

If a vigorous cold front is near, they may reach speeds of 80-100km/h.

Once formed, their motion is dependent on the movement of the parent thunderstorm.

Generally agreed they don't exceed 450km/h.