What is widely being referred to as a ‘rain bomb’ in Queensland and New South Wales is actually something else entirely.
The term ‘rain bomb’ has long been a nickname for what meteorologists call a wet microburst – when wind and rain combine to create a brief, intense downpour over a specific area.
These kinds of downpours typically last five to 10 minutes.
“‘Rain bomb’ and ‘weather bomb’ are not technical terms,” Weatherzone meteorologist Ben Domensino told The New Daily.
Meteorologist Jane Bunn from 7News and JanesWeather.com said that these wet microbursts are isolated incidents, whereas the current heavy rain has been more widespread.
What Australia is actually experiencing is an atmospheric river, according to Mr Domensino.
“An atmospheric river is a simply a long stream of wind that is blowing across a large area of the ocean, which causes a river of airborne moisture to flow through the atmosphere,” he said.
“In this case, the atmospheric river flowed towards eastern Australia, where it fuelled rainfall in parts of south-east Queensland and eastern NSW over the space of about one week.”
The atmospheric river fed into a serious of low-pressure troughs and a low-pressure system to create the torrential downpours we’re seeing now.
Ms Bunn told TND that because ‘rain bomb’ is a colloquial term, it is sometimes used interchangeable with a ‘bombing low’.
“The current low didn’t deepen rapidly enough to technically be a bombing low, but it produced the weather associated with it,” she said.
The Bureau of Meteorology has never used the term ‘rain bomb’ in its online storm and flood warnings.
When did we start hearing about ‘rain bombs’?
The term has largely been thrown around by politicians, not meteorologists.
Brisbane Lord Mayor Adrian Schrinner used the term on Sunday, February 27, just after parts of the CBD became submerged by flood water.
It was then picked up by other non-meteorological authorities.
“This was an unpredictable event, an unpredictable rain bomb over the entire south-east Queensland,” Premier Annastacia Palaszczuk said the following day.
“No one could have foreseen that in the three or four days, and in some areas, you got one year’s worth of rainfall in one to two days.”
That’s when news outlets around the country – and even The New York Times – began using the term ‘rain bomb’ in headlines.
Meanwhile in NSW, Premier Dominic Perrottet referred to the storm as a “one-in-a-1000-year event”.
Meteorologists have also hit back at this wording.