About this product
The Heatwave Forecast is a set of graphical maps of heatwaves, severe heatwaves and extreme heatwaves for the current day extending out for the next four days.
- Why were these colours chosen?
The yellow colour chosen for heatwave to allow for the warmer colours of orange and red to indicate rising severity. The changes in colour satisfy the Vision Australia recommendations for colour blindness.
- What is a heatwave?
Three days or more of high maximum and minimum temperatures that is unusual for that location.
Until the introduction of this new Pilot Heatwave Forecast there was no national definition that described heatwave or measures of heatwave severity.
- What is heatwave severity based on?
Every location across Australia has its own unique climatology of heat. The bulk of heatwaves at each location are low intensity with local communities expected to have adequate adaptation strategies for this level of thermal stress. Less frequent, higher intensity heatwaves are classified as severe and will challenge some adaptation strategies, especially for vulnerable sectors such as aged or the chronically ill. Even rarer and exceptionally intense heatwaves are classed as extreme and will challenge many normally reliable sectors, including power and transport infrastructure and anyone who does not adopt protective adaptation strategies.
- What is heatwave intensity?
Heatwave intensity is a function of the maximum and minimum temperature over a three-day period and how this relates to climatology at every location, including how this function has changed over the last thirty days.
In other words the heatwave intensity identifies unusually hot conditions sustained for three days. The service also considers conditions over the preceding thirty days to include the degree of acclimatisation which may exacerbate or ameliorate the significance of the heat.
- What will the Pilot Heatwave Forecast look like?
The Pilot Heatwave Forecast will consist of a panel of five maps across Australia for days 0 (today) to day 4. Each map will show areas where Heatwave conditions are forecast to occur and will also indicate whether their intensity is expected to reach Severe or Extreme status.
Each map examines conditions over a three-day period but consecutive maps help indicate Heatwave conditions persisting for many days.
- The Map shows areas affected by heatwave, severe heatwave and extreme heatwave. What are the differences between these levels of severity?
Areas of Heatwave are described in yellow and within these areas higher categories of Severe or Extreme Heatwave may be described.
Areas of Heatwave can expect unusually hot conditions sustained for three days. The level of heat expected is unusual but injury to people is not generally expected unless inappropriate activities are conducted or sensible precautions are not are undertaken.
In areas of Severe Heatwave vulnerable people are at risk of injury.
Areas of Extreme Heatwave are likely to cause impact across multiple areas such as infrastructure, transport, energy, agriculture and both healthy and vulnerable people are at risk of injury.
- Why a pilot service?
The science behind the service is robust and can be applied anywhere across the globe.
The service is a pilot in the sense that it is not fully integrated with the Bureau's other forecast and warning services at this early stage. This means that there will not be guaranteed notification of heatwaves within other forecast products, and the product may not be available in the event of a system malfunction.
There is opportunity for users to give feedback. Helping to inform and assist the Bureau in working towards a routine service proposal.
- Who will benefit from this Pilot Heatwave Forecast product?
Heatwaves have a range of economic and planning impacts across a broad range of sectors, namely healthcare, energy, agriculture and emergency services. This includes reducing mortality and injury to people.
A range of knock-on effects ranging from loss of power, to disruptions to transport and critical infrastructure, have a significant economic impact on business, industry and people. With longer lead times, allowing for better planning, these impacts can be mitigated.
- Australia is a hot country so why do we need a heatwave service?
Severe and extreme heatwaves have taken more lives than any other natural hazard in Australia's 200 year history. For example, during the 2009 Victorian bushfires, 173 people perished as a direct result of the bushfires, however 374 people lost their lives to extreme heat in Victoria in the heatwave before the bushfires.
- How can people use this service?
This service will give people advance notice of unusually hot conditions allowing government, emergency services and people time to adjust and to adopt measures to reduce the impact.
- Why have heatwaves been described as a 'silent killer'?
Heatwaves are not associated with violent weather such as tornadoes, cyclones or severe thunderstorms.
Heatwaves can result in significant stress on vulnerable people. This stress may result in death during the heat event but in many cases this can occur well after the cessation of the heatwave.
Often the cause of death during a heatwave is difficult to determine with many people who succumb often having pre-existing conditions.
- Is climate change a factor in an apparent increase in the number and severity of heatwave events?
Climate projections show that extreme heat events are expected to occur more often and with greater intensity in the future.
- When does a heatwave end?
Heatwaves finish when temperatures fall to more normal levels.
The maps provided by the Pilot Heatwave Forecast will reduce severity level or remove the indication of heatwave before the heatwave ends. This occurs because the maps are calculated across a three-day period. If the temperature is lower on the last day(s) then the map will indicate a lower risk despite unusually hot conditions being present for the first day or two.
Users are strongly recommended to monitor actual temperature forecasts for their location to understand when cooler conditions are expected to commence and therefore when the heatwave will finish.