Storms and their observation
The storm confirmation tool produces reports based on observations received by the Bureau within a 50 km radius of the selected location. The phenomena associated with thunderstorms are discussed below.
Thunder and lightning
Thunder is the sound caused by the electrical discharge of lightning. Hence a thunderstorm is always associated with lightning. Lightning can occur between the cloud and the ground (known as 'cloud-to-ground' lightning) or between clouds (known as 'cloud-to-cloud' lightning). Lightning sensors detect both types of lightning.
A thunderstorm is reported to have occurred if lightning was sensed within 50 km of the location, or if thunder was heard at an observing station. Thunder will only be heard if a thunderstorm is within several kilometres of a staffed observing station.
Sustained winds (10 minute average wind speeds) above 50 km/h (27 knots) are classified as strong, and along with short-term wind gusts above 90 km/h (48 knots), may cause damage to property. Topography and terrain can cause localised wind gusts, which may be stronger than those detected by our sparse observation network.
As our observation network utilises many stations that only record wind speeds on an hourly or three hourly basis, a strong wind gust could occur between these observation times and therefore not be presented in the search results.
Any thunderstorm can be associated with strong gusty winds caused by downdraughts within the storm. These downbursts can be relatively localised and as such not detected by our wind observation network.
Thunderstorms are often, but not always, associated with intense showers of rain. These can cause damage to property as a result of associated flash flooding, overflowing gutters, erosion, etc. Rainfall data are not provided in the thunderstorm confirmation tool, however daily data for the last 14 months are available from Daily Weather Observations. Additional rainfall stations and earlier daily rainfall data are available from Climate Data Online.
A severe thunderstorm is defined by the Bureau of Meteorology as one which produces:
- Hail with a diameter of 2 cm or more (about the size of a $2 coin); or
- wind gusts of 90 km/h (48 knots) or greater; or
- flash floods; or
- tornadoes; or any combination of these.
Some historical severe storm information is also available in the Severe storms archive.
Lightning observation data
The current supplier of Bureau of Meteorology lightning strike data is Global Positioning and Tracking Systems Pty. Ltd. Other companies offer similar services, such as Kattron. Please contact these companies if you require specific data or information about lightning strikes. The Bureau is unable to supply this data directly.
If you have any questions about a particular storm event or about this service please send us an enquiry.