Health advisory:
Date Issued:
29 Nov 2016 - update to Alert issued 22 November 2016
Issued by:
Professor Charles Guest, Chief Health Officer
Issued to:
Health professionals, members of the community

Key messages

  • Ambulance Victoria and hospital emergency departments saw a significant increase in patients presenting with respiratory symptoms following the thunderstorm event on the evening of 21 November 2016.
  • Thunderstorms have been linked to epidemics of asthma symptoms, especially during the grass flowering season which is typically October to mid-December.
  • Review existing asthma management plans for all patients with asthma and review patients who experience symptoms for the first time.
  • An asthma attack can be life threatening. Anyone experiencing wheezing, chest tightness and difficulty breathing should call 000.

What is the issue?

Thunderstorms have been linked to epidemics of asthma symptoms due to the fragmentation of pollens and the disturbance of other environmental allergens, especially during the grass flowering season.

The thunderstorm of 21 November 2016 saw a significant demand on Ambulance Victoria and hospital emergency departments from patients presenting with respiratory symptoms.

Epidemic thunderstorm asthma events are infrequent and difficult to predict. However, they occur during hayfever season (October to mid-December). It is therefore important that people are aware of this phenomena and act on any respiratory symptoms that develop.

Who is at risk?

Anyone could experience asthma symptoms during an epidemic thunderstorm asthma event.

Those with a history of asthma, allergies or hayfever (allergic rhinitis) are at increased risk. The risk appears to be widespread during the grass flowering season, which is typically October to mid-December.

Importantly, those with asthma can reduce their risk by adhering to their asthma management plan, including their regular medications.


These are the same as regular asthma symptoms and include:

  • coughing
  • wheezing
  • difficulty breathing
  • tightness in the chest.

If there are signs that a person's condition is deteriorating, urgent care should be sought. Signs of rapid deterioration include little or no relief from their reliever inhaler, they are unable to speak comfortably, or if their lips are turning blue. This requires urgent care from medical providers.

Treatment information

Patients should be advised to seek review if they are concerned about their asthma. Asthma management plans should be reviewed and patients should ensure they have an adequate supply of their medications (including relievers). It is also important to emphasise the importance of patients continuing with any prescribed preventer medication.

If a patient thinks they are having an asthma attack, they should follow the instructions in their Asthma Management Plan or seek urgent care as appropriate.

Patients with known allergic rhinitis (hay fever) or rye grass allergies, may wish to stay inside on high pollen and windy days and during a thunderstorm. However, they should be reminded that this may not necessarily prevent respiratory symptoms and that they should remain alert to signs of asthma symptoms worsening.


Pollen forecasts alert those who suffer from hay fever and seasonal asthma of the likelihood of being exposed to high levels of grass pollen, enabling sufferers to take preventative measures in danger periods.

People with asthma or hayfever (allergic rhinitis) should, as always, use their usual medications, know the signs of worsening asthma and the asthma first aid steps and try to stay inside on high pollen and windy days, and during and after a thunderstorm. They should remain alert to the signs of asthma worsening and encourage friends and family members to undertake basic First Aid training.

More information