How would it affect modern cities and landscapes if they were burned with an huge amount of fire?

[Postapokalypso]

Okay, forgive me for my non native english "skills" here. The question might sound weird at first?
Basically I want to destroy my fantasy world, which is a variation of our world, by letting it be burned down by dragons. Let's suppose the dragonfire is stronger and hotter than normal fire but nothing else. Only that the dragons are enormous and that there are enough of them to cover entire cities in flames.

How would buildings, streets, nature and so on be affected by that? Would they collapse? Burn? How long does nature take to recover from such fire and what kind of landscape will form afterwards?
As you see I know nothing about fire, I'd be glad for some wise wizards to help me

 

[Devor]

All the burning isn't bad for the soil, and the dead plant and wild life just provides extra nutrients. If there are herd animals that escape the dragonfire, the plant life should recover quickly and even grow stronger than it was before. If there are no herds, much of what's lost will recover, but some will remain barren. That's because herds play an important role in compressing the soil and packing the nutrients together. Farmers with any sense of irrigation should be able to recover their farmlands. Wildlife should be able to enter from nearby areas, unless something keeps that from happening. The ecosystem should show a full recovery within a decade, which is how long it will take the trees to grow.

The destruction of the city would be immense, but beyond that I think someone else will have a better answer.

 

[K.S. Crooks]

When it comes to the cities buildings will have a mixed effect. The exteriors of most buildings can withstand fire and other disasters, it's the insides where the weakness are found. If the windows are open or for office building are broken and the fire can reach the inner walls and furnishings then it will spread faster and become far more intense. This would cause building in this situation to collapse if the inner beams can be heated to structural failure. Perhaps look at footage from cities where major fires have occurred.

 

[pmmg]

I suppose I must first ask what period is this in? I might assume a standard medieval type setting, but it would matter. It took about 100 days for the fires at the World Trade centers to burn out, and they were not the whole of the city.

Rome burned down while Nero played, it most of it was lost in about a week.

In direct answer to these questions:

How would buildings, streets, nature and so on be affected by that? Would they collapse? Burn? How long does nature take to recover from such fire and what kind of landscape will form afterwards?


I am pretty sure all buildings would be burned to ash and not much of them would be left standing, not even frames. (If these are more steel and concrete buildings, you might look at the destruction of Dresdon for an example of destruction by fire).

If people did not return to the site, it would be reclaimed by nature. In fact, it might even thrive there after a short time. Maybe a summer or two for seeds to blow and plants to sprout up, and becoming more and more lush as time went on. Animals would almost certainly quickly populate the site. Scavengers at first, that just about anything that was native to the area.

If people were to return and rebuild, well, then I suspect they would just build another city, at their own pace, according to their population.

The pace of nature re-growing over the old city would also be adjusted by the types of buildings and roads left behind. Concrete would take longer to be reclaimed than ash and dirt. A city like New York, destroyed by fire, I would expect would become mostly reclaimed by nature over a period of 100 years or more, and probably several thousand before there was no trace of it left. A city with mostly wooden structures and dirt or loosely paved roads, just a few years. Maybe as long as 50 before it was unrecognizable from the surrounding lands, or would require archeology to piece it back together.

I am thinking I would need more input from you before I could attempt to help further.

Edit: I missed the title which does say a modern city.

100's to 1000's of years to be over taken by nature and to be reduced to have little or no trace. There was a television series called "life after people' they tried to answer questions like these. It did not really say the world had suffered fire, but the nature reclaiming parts would still seem relevant. Maybe you can find.

 

[CupofJoe]

When you get large fires then you can get a thing called a Fire Storm. There is so much heat and hot air it creates it's own localised winds sucking in more fresh air and making the fire worse. This happens in natural fires as well a created ones. Embers from the fires will travel a long way and start more fires. There are even examples/tales of thinge bursting in to fire, just from the heat aroiund them. During the Second World War, several cities were fire bombed [small bombs designed to create fires rather than big bombs deisgned to knock things down] and while the bombing raid may have lasted six hours the firesraged for days. For graphical evidence I try a search on places like Dresden, Tokyo, Hamburg. In Dresden a few hundred died from the actual bombing but maybe as many as 30 thousand more died from the fire that followed. I think the fire bombing of Japanese cities may have been far worse because their usual construction was with far more wood.

 

[Postapokalypso]

Thanks for all the answers! Thats really great, i'm glad I found this forum.
Especially the thing with the fire storm looks promising to me. Not that the fire is a big part of my story, but it's the thing everything else is based on.
It would bascially play sixty years after the citys have burnt down and humanity is not allowed to settle back into a modern lifestyle, the ones that survived that is.

But anyways, I wanted to be able to imagine what the citys would look like, if a person walked into them sixty years later. I'll also search for the "life after people" series, that sounds really promising! Thanks again, this helps a lot!!

 

[Dark Squiggle]

When you get large fires then you can get a thing called a Fire Storm. There is so much heat and hot air it creates it's own localised winds sucking in more fresh air and making the fire worse. This happens in natural fires as well a created ones. Embers from the fires will travel a long way and start more fires. There are even examples/tales of thinge bursting in to fire, just from the heat aroiund them. During the Second World War, several cities were fire bombed [small bombs designed to create fires rather than big bombs deisgned to knock things down] and while the bombing raid may have lasted six hours the firesraged for days. For graphical evidence I try a search on places like Dresden, Tokyo, Hamburg. In Dresden a few hundred died from the actual bombing but maybe as many as 30 thousand more died from the fire that followed. I think the fire bombing of Japanese cities may have been far worse because their usual construction was with far more wood.

The Japanese firebombings were worse for two other reasons as well. 1)The Americans had mercy for the Germans, but not the Japanese, and bombed the Japanese much more harshly, and 2) The B-29 was deployed in Japan, while in Germany, only older and inferior American and British bombers were used.
You could also look at the burning of Chicago https://www.google.com/url?sa=t&rct...Chicago_Fire&usg=AOvVaw0-idB-eXg3BrAG7-fimCg5

 

[pmmg]

Here is a link to one of the episodes. Does not look promising for reclaimed by nature in 60 years. But, they are not starting with the cities being burned to the ground to start with. You will have to make your own adjustments after that. Still, I think you are talking hundreds of years for the remnants of the city to have been so overgrown that they are unrecognizable..