How 'thunderstorm asthma' pushed Melbourne to the edge
It was the seemingly typical thunderstorm that rapidly escalated into a "disaster event".
When dark clouds gathered over Melbourne, Australia, late on Monday local time, Victoria's emergency services braced for reports of damage and possible injury.
Instead, the storm brought something far worse - a rare phenomenon called "thunderstorm asthma" that stretched paramedics and hospitals to their limits, BBC reports.
So how did it catch everyone by surprise?
Ambulance Victoria received more than 1,870 calls between 18:00 (07:00 GMT) and 23:00 on Monday, a number more than six times the daily average.
The massive increase affected waiting times and forced 60 reserve ambulances, police and fire-fighters to respond to medical emergencies.
"It was an extraordinarily busy, it was unprecedented," said Mick Stephenson, Ambulance Victoria's executive director of emergency operations.
He said about 200 calls were directly linked to asthma, but 600 more reported respiratory issues.