On the evening of Monday 21 November 2016, Melbourne experienced the largest ever recorded “Thunderstorm Asthma” event. After a particularly hot day a dramatic cool change arrived with thunderstorm activity and strong westerly winds. Within a short period many thousands of people across Melbourne developed breathing difficulties. There was a huge spike in calls to emergency services (000) and emergency department attendances. In the 30 hours from the start of the event there was a 1000% increase in asthma-related admissions to Victorian hospitals when compared with the 3-year average. Tragically, nine deaths occurred which can be directly attributed to the Thunderstorm Asthma event.