What is epidemic thunderstorm asthma?
During grass pollen season (1 October to 31 December) people may notice an increase in asthma and hay fever. Grass pollen season also brings the chance of epidemic thunderstorm asthma.
Thunderstorm asthma is thought to be triggered by a unique combination of high amounts of grass pollen in the air and a certain type of thunderstorm. For people who have asthma or hay fever this can trigger severe asthma symptoms.
When a large number of people develop asthma symptoms over a short period of time, related to high grass pollen and a certain type of thunderstorm, it is known as epidemic thunderstorm asthma.
Preparing for epidemic thunderstorm asthma
Everyone in the community should know the signs and symptoms of asthma, and know the four steps of asthma first aid so they know what to do if they or someone is having an asthma attack.
Thunderstorm asthma can affect those with asthma or hay fever - especially people who experience wheezing or coughing with their hay fever.
All people at increased risk of thunderstorm asthma should:
- learn about epidemic thunderstorm asthma and what you can do to help protect yourself and those in your care during the grass pollen season
- check the epidemic thunderstorm asthma risk forecast daily
- where possible, avoid being outside during thunderstorms from October through December – especially in the wind gusts that come before the storm. Go inside and close your doors and windows, and if you have your air conditioner on, turn it to recirculate
- have an asthma action plan (if you have asthma) and have practical knowledge of the four steps of asthma first aid
- have reliever medication appropriately available in grass pollen season and be aware of how to use it (ideally with a spacer)
- be alert to and act on the development of asthma symptoms as explained in your asthma action plan (if you have one), or if you don’t, use asthma first aid.
- If you have asthma symptoms see your doctor for advice
More information about protecting yourself if you have asthma can be found on the Better Health Channel.
What do the forecasts mean?
The epidemic thunderstorm asthma risk forecast will operate between 1 October and 31 December. It combines the forecasting of a certain uncommon type of thunderstorm and grass pollen levels across Victoria.
It spans three days (today, tomorrow and the day after) and uses a colour-coded scale from low to high risk: green (low), orange (moderate) and red (high).
- A low risk (green) forecast means that the elements necessary for an epidemic thunderstorm asthma event are not expected and an event is unlikely.
- A moderate risk (orange) forecast means that one of the elements necessary for an event may be present (i.e. a high pollen forecast or a severe thunderstorm storm with strong winds) and there is a moderate chance of an epidemic thunderstorm asthma event occurring.
- A high risk (red) forecast means that a high pollen forecast and severe thunderstorm(s) with strong winds are likely to be present increasing the risk of an epidemic thunderstorm asthma event occurring.
Forecasts are not a formal 'warning' and are designed to inform people at risk that they should be prepared. The forecast only indicates whether the chance of an epidemic thunderstorm asthma event occurring is increased – a higher forecast does not mean that an event is certain to happen, nor does a lower forecast mean that an event will not happen.
The forecasting system is also not designed to forecast the risk of individuals experiencing asthma and hay fever symptoms, which occur every year during the grass pollen season.
On a high risk day the department will issue up-to-date relevant advice and warnings on the VicEmergency warning platform.
The forecast for the current day is only updated once at approximately 12:30pm, any further updates (such as public advice and warnings) will be posted on the VicEmergency website and app.
