•They are localised disturbances in the
atmosphere accompanied by thunder, lightning
rain, snow or hail.
•They can occur anywhere in Australia and are
responsible for more damage (as measured by
insurance costs) than tropical cyclones,
bushfires or earthquakes.
• Storms develop when warm moist air rises rapidly in an
• Sometimes this upward movement is initiated by the
passage of a cold front.
• On other occasions (often in summer), the heating of the
earths surface is enough to start the rapid upward
movement of the air.
• Most of these storms do not reach the level of intensity
needed to produce widespread damage, but they all
produce lightning, which can cause death, injury and
• Sometimes they are accompanied by hail, wind gusts and
Impacts• Each year, on average, severe thunderstorms
are responsible for more damage (as
measured by insurance costs) than tropical
cyclones, earthquakes, floods or bushfires.
• Unfortunately, thunderstorms also kill people
- between 5 and 10 deaths are caused by
lightning strikes each year. More deaths
occur when strong winds cause tree limbs to
fall, debris to become projectiles and small
boats in open water to capsize.
WHEN A SEVERE THUNDERSTORM APPROACHES
Listen to your local radio station for thunderstorm warnings.
Shelter and secure pets and animals.
Put garden furniture, toys, etc. inside. Fill garbage bins with water to
hold them down.
Park vehicles under solid shelter or cover with firmly tied
Secure all external doors and windows and draw curtains.
Put valuables, medications and spare warm clothing in plastic bags
with your emergency kit and keep handy.
Disconnect all electrical items, external TV/radio aerials and
Key Geographical processes
• Thunderstorms develop when warm,
humid air near the ground receives an
initial upward push from converging
surface winds and rises rapidly in an
• Thunderstorms can become severe when
the atmosphere is particularly unstable
and/or additional energy is drawn in from
Useful Map/ Diagram