A Fire conversion: hectares to km of highway

Australia is in the early stages of summer, and a huge swathe of it is under fire. Unfortunately, numbers just don’t really seem to add up to anything that the brain can cope with. This is yet another meagre attempt. Beware: the maths should be ok, but there might be mistakes!

The fire closest to me is 46000 hectares in size, it was started as an ember fire from another, larger fire to the west which is currently 470000 hectares. Last week I had to drive around these fires for business: it was a 3hr drive to get to the other side.

That night, just after arriving home again, the main fire, being so big and generating it’s own ‘micro-‘ climate, created a thunderstorm which set off a few dozen (or so) fires around it. Those little fires grew rapidly and have largely joined up to form roughly 140000 hectares of fire front in their own right.

In ballpark figures, the fires near me total well over 650000 hectares. Yes, that’s 4 zeroes. It’s a meaningless number, it’s so big. So let’s explore this size:

1 Hectare

One hectare is an SI unit defined as 100m by 100m.


My parents have a small property (by Australian standards). It’s 22 acres, or around 9 hectares in size and takes a good 10 minutes to walk from one end to the other (opening and closing gates).

10 Hectares

… is the equivalent of:

  • 10 running tracks
  • A 5km section of highway (Assuming a 4 lane highway with break down lanes and divider is roughly 20m wide)

100 Hectares

… is the equivalent of a 50km section of highway. It takes a decent 30 to 45 minutes to drive this distance.

1000 Hectares

… is 500km of highway. This is the equivalent 1/2 way from Sydney to Brisbane. Actually it’s the almost the same as Sydney to Coffs Harbour (525km), where fires have been burning for months. That’s well over a 5 hour drive.

The main fire near me was growing around 5000 hectares a day, but on the bad days it grew 15000 hectares. That’s 2500 – 7500km of highway, per day, every day for several weeks. The smoke (& subsequent dust from the drought) reaches New Zealand, and even New Caledonia.

The orange haze in Central Otago. Image: Twitter/Dale Wowk

650000 Hectares

This is the current size of the fires near me. I’ve not seen a clear night sky in weeks. I’ve bought carbon filter dust masks for during the day and an air purifier for when I’m at home & during the night. Both are very poor substitutes for fresh air. Black leaves started falling on the property 6 weeks ago and every morning there’s ash on the cars. At the end of it all, the fire will end up even much larger than this, unless rain comes. Unfortunately, rain is not due for another month or so.

650000 Hectares is the equivalent to:

  • 325000km worth of highway.
  • over 80 laps around the state of NSW (total area = 800000 sq km, perimeter is approx 4000km)
  • just over 9 complete laps around the mainland of Australia (perimeter is slightly over 35000km)
  • 151 trips of Sydney to Auckland, New Zealand (2156km).
  • 8 trips around the Earth.
  • 80% of the way to the moon (405000km away), using a 4 lane highway. If we were to stack people shoulder to shoulder (width 1m, height 1.8m) we’d end up with the equivalent of 16 trips to the moon (& need 3.6 million people to stack up).

This is what 650000 hectares of fire zone looks like. As you can see it’s not even the biggest fire area:


3 Million Hectares

This is the reported size of the fires in Australia at the moment. I have no words to describe the size of it. Our volunteer fire-fighters go out every day exhausted, and return home even more so.