This Astronomical Figure Explains Just How Much Rain Townsville Copped

We understand natural disasters through a human face, but sometimes the numbers tell the real story.

People in Townsville are starting to mop up after the worst flooding in memory, as more than a week of intense rainfall finally subsides.

Insurance losses are already estimated to be over $100 million (and mounting), with a similar dollar value put on infrastructure losses.

But if you're looking at raw numbers -- as opposed to the heartbreaking human face of this natural disaster -- it's the rainfall figures that are most astounding.

It's hard to convey just how much rain has fallen in Townsville and surrounding areas, but here's our best shot:

  • In seven days so far this month, 880 mm of rain has fallen in Townsville;
  • In total, 1303.6 mm has fallen since the rain started on January 27.

But what does this mean?

How much exactly is 1303.6 mm of rainfall?

Well, it's:

  • A lot more than Townsville's annual average rainfall of 1128 mm;
  • That's right, the city exceeded its entire year's average rainfall before the end of the first week of February;
  • It's also more than Sydney's average annual rainfall of 1215 mm. And Sydney is a pretty wet place;
  • And it's more than double London's annual rainfall;
  • It's also, in raw terms, 130 cm or 1.3 metres. Imagine trying to fill a blow-up backyard pool that deep, just with rain. Now you get a sense of how much rain has fallen in 10 days.

The persistence of the rain in wide areas of north Queensland is well illustrated below.

READ MORE: Two Bodies Found In Townsville Floodwaters

READ MORE: Townsville Locals Pull Together After Deadly Floods

But why did it happen?

"This rain event was due to two systems combining -- a slow moving and vigorous monsoon trough with an embedded tropical low," 10 News First Queensland weather guru Josh Holt told 10 daily.

"The fact that the trough was so slow moving allowed allowed heavy rainfall to fall over parts of the Townsville catchment for days on end, which led to sharp river rises and increased dam levels."

Holt said that Australia has seen numerous slow-moving weather systems in in recent months. First it was slow-moving high pressure systems that led to the heatwaves. Now it's slow-moving lows.

"We've we seen both ends of the spectrum with these slow-moving systems," he said.

Meanwhile, as we publish this story, rain has just started in Townsville again.  This is the Townsville radar just after midday in Queensland on Thursday. The green and yellow patches indicate moderately heavy rain.

Source: BoM