National flood warning system
We provide flood forecasting and warning services in each Australian state and territory, as part of the national Total Flood Warning System.
To do this, we work with:
- emergency management agencies
- government departments with responsibility for water management
- water authorities
- local councils.
The services we provide for each state and territory are outlined in service level specification documents on this page.
Our role in flood warnings
There are many aspects to flood forecasting and warning. These include:
- weather and water observations
- forecasting and modelling flood scenarios
- dam operator information
- decision-making and response
- review and testing.
We work closely with state and territory governments, local councils and state emergency services (SES) to interpret the data and inform the community. Learn more about how we work with emergency services on our Emergency management page.
We're responsible for monitoring and predicting riverine floods. In this process, we can issue a Flood Watch or a Flood Warning.
We also issue a Flood Scenarios Outlook to help emergency services agencies plan and prepare for riverine flooding. It provides detail on the likely size and timing of flooding over the next seven days, based on two different rainfall scenarios.
State, territory and local governments are responsible for providing flash flood warnings.
Learn more about the difference between flash flooding and riverine flooding.
Understanding Flood Watches and Flood Warnings
There are different types of floods which have different warning levels to help you prepare and act according to the information that we provide.
Our flood warnings are issued as:
- a Flood Watch
- a Flood Warning
- or a Severe Weather Warning.
Riverine flooding occurs when rainfall saturates a catchment and excess runoff moves into waterways, causing river levels to rise. When this is likely, we issue a Flood Watch for the impacted area. This gives you early advice that riverine flooding may occur – so you can prepare. This isn't a warning of imminent flooding.
When flooding is imminent or already occurring, we issue a Flood Warning. This means you should take action – and follow the advice of your local emergency services. Sometimes, we can also experience short bursts of intense rainfall which can lead to rapid-onset flooding – known as flash flooding. When flash flooding is likely, we issue a Severe Weather Warning for the impacted area.
We'll issue a Flood Watch up to 4 days before flooding is expected. This is because a Flood Watch is based on forecast rainfall. We update Flood Watches at least once per day. In most areas, we keep the Flood Watch in place until the areas included are covered by a Flood Warning – or the risk of flooding has passed.
Not all areas that receive a Flood Watch will receive a Flood Warning. An area may experience flooding without a Flood Watch being issued. A Flood Watch covers a broad region. Sometimes we know there will be a lot of rain coming but we can't determine exactly where that will fall. Therefore, not every location within the Flood Watch will experience flooding. A Flood Warning will cover a more specific area, when we become more certain that flooding is expected.
A Flood Watch provides important information about:
- forecast rainfall totals
- developing weather conditions
- the catchments at risk of flooding
- if roads and communities may be affected
- and how to get flood safety advice from your local emergency services.
We work closely with emergency services in each state and territory, providing information to help with flood preparedness, response and recovery. For information on how to prepare for a flood emergency – visit your State Emergency Service website.
For emergency help in a flood – call the SES in your state on 132 500.
And in a life-threatening flood emergency call 000.
For more information about floods – visit the flood knowledge centre on our website. Stay up-to-date with the latest forecasts and warnings in your area via the Bureau website or the BOM Weather app.
Flood Watch
We issue a Flood Watch when forecast rainfall and catchment conditions suggest that local and riverine flooding is possible. Its purpose is to provide early advice of a developing weather situation that may lead to flooding. A Flood Watch isn't a warning of imminent flooding.
A Flood Watch:
- provides information about a developing weather situation and catchments at risk of flooding
- may indicate how severe a possible flood might be
- includes links to current warnings, other flood-related information, and contact details of relevant emergency services.
Flood Watches can be issued up to 4 days in advance of potential flooding. They are updated at least daily and finalised once all catchments mentioned in the Flood Watch are covered by Flood Warnings or the risk of flooding has passed.
The Flood Watch service:
- covers the whole country
- includes catchments where there is no riverine flood warning service.
We work with key agencies in each state and territory to define and review flood watch areas to make sure they are locally relevant.
Flood Warning
We issue a Flood Warning when riverine flooding is likely or occurring at a particular location.
What's in a Flood Warning
A Flood Warning:
- is more targeted in time and place than a Flood Watch
- is issued for specific catchments and locations within catchments
- includes a forecast of how severe and when the flood is likely to be.
The Flood Warning typically includes predictions about the level the river is likely to rise to, and the timing of this. Where less data is available, it may include a statement about future flooding that is more general. For example:
'River levels are elevated along the Coal River around Richmond and are expected to remain elevated into Wednesday.'
The type of information we provide depends on the:
- quality and spatial coverage of real-time rainfall and river-level data available
- capability of rainfall and hydrological forecast models and tools
- level of service agreed with partner organisations.
Generalised flood warnings
When there is not enough data to make specific predictions, or in the developing stages of a riverine flood, we provide generalised flood warnings.
These are based on forecast rainfall and knowledge of historical flood response.
Generalised warnings advise that flooding is likely in particular catchments but don't provide information about how severe the flood may be or predictions for precise locations.
Warning about flash floods
State, territory and local governments are responsible for providing flash flood warnings.
We note the potential for heavy rainfall that may lead to flash flooding in Severe Weather and Severe Thunderstorm Warnings.
Flash floods happen very quickly, typically occurring within six hours of the rainfall that caused the flood.
We are responsible for providing riverine flood warnings, which typically cover larger rivers that take more than six hours to respond to rainfall.
As riverine flooding takes longer, we can work with our government partners to:
- collect data
- run prediction models and tools
- interpret flood mapping and impacts
- determine potential consequences
- issue and communicate warnings.
This isn't possible for flash floods, given how fast they happen. For more information about severe weather services, see our Severe weather knowledge centre.
Service level specifications for floods
These documents detail the flood forecasting and warning services that we provide for each Australian state and territory. This includes:
- types of products and services we issue
- catchments and locations forecasts and warnings are provided for
- river heights that trigger Flood Watches and Flood Warnings
- rainfall and river data locations that are part of the flood warning network.
Improving Australia's flood warning network
We're delivering a 10-year program to acquire and upgrade flood warning infrastructure. The National Flood Warning Infrastructure Network (FWIN) Program focusses on critical catchments in each state and territory. Learn about Flood warning network upgrades.