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Emergency terms explained

Road Closed sign

There are three main types of alerts you may see published on this website.

  • Advice — An emergency incident has started. There is no immediate danger. Stay up to date in case the situation changes.
  • Watch and Act —There is a heightened level of threat. Conditions are changing and you need to start taking action now to protect you and your family.
  • Emergency Warning — The highest level of alert. You may be in danger and need to take action immediately. Any delay now puts your life at risk.

Here is a glossary of other useful terms to know in order to keep safe this emergency season:

A

Air currents — Fire heats passing wind, which is carried to new locations and can heat fuel sources to ignition.

Australian Warning System — a new, nationally consistent set of standards for emergency warnings being slowly rolled out from December 2020.

Amber alert — An amber alert is issued by police forces asking for public assistance to locate a child in either a child abduction or high-risk missing child case.

B

Bushfire all clear — The danger has passed and the fire is under control, but you need to remain vigilant in case the situation changes. It may still not be safe to return home. This term is not used in all jurisdictions.

C

Cyclone - Category one — Destructive winds. Negligible house damage. Damage to some crops, trees and caravans. Craft may drag moorings. A category one cyclone's strongest winds are GALES with typical gusts over open flat land of up to 125kph.

Cyclone - Category two — Destructive winds. Minor house damage. Significant damage to signs, trees and caravans. Heavy damage to some crops. Risk of power failure. Small craft may break moorings. A category two cyclone's strongest winds are DESTRUCTIVE winds with typical gusts over open flat land of 125 to 164kph.

Cyclone - Category three — Very destructive winds. Some roof and structural damage. Some caravans destroyed. Power failures likely. A category three cyclone's strongest winds are VERY DESTRUCTIVE winds with typical gusts over open flat land of 165 to 224kph.

Cyclone - Category four — Significant roofing loss and structural damage. Many caravans destroyed and blown away. Dangerous airborne debris. Widespread power failures. A category four cyclone's strongest winds are VERY DESTRUCTIVE winds with typical gusts over open flat land of 225 to 279kph.

Cyclone - Category five — Extremely dangerous with widespread destruction. A category five cyclone's strongest winds are VERY DESTRUCTIVE winds with typical gusts over open flat land of more than 280kph.

Cyclones in WA

Cyclone - blue alert — Get ready for a cyclone. You need to start preparing for cyclone weather.

Cyclone - yellow alert — Take action and get ready to shelter from a cyclone. You need to prepare for the arrival of a cyclone.

Cyclone - red alert — Take shelter from the cyclone. You need to go shelter immediately. Do not drive on red alert.

Cyclone watch — A category one to five cyclone is expected to affect coastal communities within 24 to 48 hours.

Cyclone all clear — The cyclone has passed but take care. Wind and storm surge dangers have passed but you need to take care to avoid the dangers caused by damage.

E

Earthquake magnitude 5.4 or less — Unlikely to result in anything other than minor damage.

Earthquake magnitude 5.5 to 6.1 — Causes slight building damage, plaster cracks and bricks fall.

Earthquake of magnitude 6.2 or greater — Likely to result in major damage. Each state has a different lead agency for earthquakes: NSW Police, Victoria SES, WA DFES, Queensland QFES, ACT ESA, NT Police, SA Police, Tasmania Police.

F

Fire danger ratings — These give you an indication of the possible consequences of a fire if one was to start.

Flash flooding — Caused by heavy rain in a short period of time. An issue for many urban areas where stormwater drains are unable to cope.

H

Hail - giant and large — As described by the Bureau of Meteorology, large hail is 2cm in diameter or more; giant hail is 5cm or more in diameter.

Harvest ban — Ban on harvesting, driving across paddocks and the use of heat-creating equipment due to the fire threat from sparks. Issued by local government in WA only.

Harvest warning — A directive to farmers to stop harvesting, check the conditions and only proceed when safe.

Heatwave — BOM issues warnings when the maximum and minimum temperatures are unusually high for a period of three or more consecutive days.

M

Minor flooding — Low-lying areas next to watercourses are inundated which may require the removal of stock and equipment. Minor roads may be closed and low-level bridges submerged.

Moderate flooding — The area of inundation is more substantial and the evacuation of some houses may be required. Main traffic routes may be affected. In rural areas removal of stock is required.

Major flooding — Extensive rural areas and/or urban areas are inundated. Properties and towns are likely to be isolated and major traffic routes likely to be closed. Evacuation of people from flood-affected areas may be required.

P

Pandemic — An outbreak or unusually high occurrence of a disease or illness in a population or area (an epidemic) which has spread across multiple countries.

R

Riverine flooding — Flooding that causes rivers to break their banks. The Bureau of Meteorology issues flood warnings for rivers they monitor.

S

Severe weather warning  Issued by the BOM due to damaging/destructive winds with gusts of 90kph or more, heavy rain and flash flooding, abnormally high tides, large surf, coastal erosion and alpine blizzards.

Severe thunderstorm warning — Issued by the BOM for thunderstorms that are likely to cause large or giant hail, damaging or destructive wind gusts, heavy rain and flash flooding or tornadoes.

Spotting — The wind carries small pieces of burning material ahead of the fire which can ignite new fires.

Supercell — A simultaneous and intense updraught and downdraught within a thunderstorm. Supercells have the potential to be the most severe form of storm.

T

Thunderstorm asthma — A thunderstorm asthma event is when pollen is captured within brewing storm clouds and bursts, causing severe breathing problems, even in people who have never had asthma.  

Total fire ban — Tells you what you can or can't do on days when fire will spread rapidly and be out of control. Fire bans are generally issued the day before the actual ban but can be issued the same day.

Tropical cyclone watch — The onset of gales is expected within 48 hours but not within 24 hours.

Tsunami - no threat — An undersea earthquake has been detected, however it has not generated a tsunami, or the tsunami poses no threat to Australia.

Tsunami - marine and immediate foreshore threat — Potentially dangerous rips, waves and strong ocean currents in the marine environment and the possibility of only some localised overflow onto the immediate foreshore.

Tsunami - land inundation threat — Warning for low-lying coastal areas of major land inundation, flooding, dangerous rips, waves and strong ocean currents.