LA is on fire. How will Australia cope when bushfires hit Sydney, Melbourne or another major city?

As I write this, five people are dead and at least 1,000 buildings have been destroyed by wildfires that have swept across Los Angeles. Around 100,000 people have been ordered to evacuate.

We are not yet sure of the scale of the disaster, but maps show it is burning across many suburbs. That is shocking. We are looking at a disaster unfolding in real time.

But we knew this would happen eventually. We have moved from possible futures to these things now happening. The deferment has ended.

So, could something similar happen in major Australian cities – and how prepared are we? The answers are: yes, and not very.

Why is LA on fire?

The areas north of LA have always been at high fire risk. That’s because of the mix of the fuels from trees and plants and the uneven terrain; canyons and ridges can accelerate fire.

But in this situation, several things happened at once – all of which are bad.

We had the amazingly strong Santa Ana winds, in conjunction with a very dry landscape. The landscape was primed for fire, and then due to these winds, the fires grew extraordinarily fast. Fire suppression capacity was quickly overwhelmed.

In a place such as California, with its enviable aerial fire-fighting capacity, fires can usually be contained rapidly. But this one grew at a fantastic rate, driven by these terrible winds. It then got into the houses and all the way down the coast.

Shockingly, it crossed from the intermix housing on the border of bushland and city, and moved into suburban environments. It was an incredibly fast escalation.

All of these things aren’t unexpected. We know fires are burning faster and hotter and quicker, and fire seasons are getting longer. After all, these LA fires happened in the US winter.

The environment is being primed by climate change and we know there are limits to fire suppression.

So, we knew these things were going to happen – but it is still so confronting when they do.

Could this happen in a major city in Australia?

The short answer: yes.

We don’t have Santa Ana winds, of course, but we do have downslope winds (a wind that comes over a topographic barrier like a mountain range). They are often very dry and warm and can move quickly.

There is the possibility for fires to burn into Australian suburbs. It happened in Canberra in 2003. And it could happen again in a major city such as Sydney or Melbourne. We have all the ingredients.

If you have the wrong wind and the wrong fire and the wrong time, a fire can be driven very quickly into an urban area.

The degree to which it would spread depends on the suburban landscape and how well prepared the area is.

If a suburb has older housing stock with older gardens, for instance, it’s absolutely ripe for a fire to spread quickly. If you have more modern housing stock (which is usually better at defending against ember attack), and the houses are more spaced apart and the gardens are clearer, then you might be OK.

When fire gets into suburbs, the damage can be variable. Some houses might burn down and others may survive. But the worst case scenario is what we call “house-to-house ignition”, where the houses become the fuel.

The other frightening dimension is what happens if water supplies run out, which is reportedly happening in some parts of Los Angeles.

How ready are Australian cities for fires?

Australia is not well prepared for scenarios such as this. But rather than be fatalistic and assume urban areas are open game for wildfires, effort is needed from all levels of government and community to reduce the risk of fires impacting suburban and semi-suburban areas.

That means better boundaries between houses and keeping fuel loads low. It also means households, councils and fire authorities having a plan for when fires hit.

This may mean implementing planning rules to enforce safer gardens or the clearing of bushland behind homes. But such measures will be controversial in many cases.

Gaining public support will require designing landscape-scale firebreaks that are attractive and sympathetic to biodiversity.

Studies suggest that achieving fire-ready cities requires a mix of research, education, incentivisation and penalties.

We also need to ask: how bushfire-aware are city residents?

So much messaging around having a plan, knowing where to go and leaving early has been targeted at rural and bushland residents. Many people in suburban areas may not consider themselves vulnerable and might not have a plan at all.

Many regional and rural areas in Australia have bushfire places of last resort – safe places for the community to go when all other bushfire plans have failed. The LA tragedy shows we also need these places in cities. People also need a plan on how to get there (by walking or going on bike, where possible), so traffic jams don’t ensue as everyone tries to escape.

People should also be educated about what to expect at the evacuation point when you arrive. Where possible, they should take their own food, water and medicines and include pets in their plan.

And the planning discussion should include residents in fire-prone areas installing their own specially designed fire-shelters at home, if they can afford it.

Nowhere to hide

Global warming is making bushfires in Australia more frequent and severe. As bushfires become more prevalent, home insurance costs are increasing. That will affect the cost of living and the broader economy.

The LA fires show when it comes to climate change, there’s nowhere to hide. Around the world, authorities and communities must overhaul their assumptions about bushfire risk and preparedness. That includes people living in cities.

Kicking the can down the road won’t work. The crisis is already here.

David Bowman has received funding from the ARC and Natural Hazards Research Australia.