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19

A definitive statement comes from the abstract of Scott and Glasspool1, 2006: Charcoal, a proxy for fire, occurs in the fossil record from the Late Silurian (≈420 Myr) to the present. One of the tired old truisms you learn is that fire needs three things: Oxygen, fuel, and a source of ignition. There is little doubt that there has been lightning since ...


12

It's a combination of both the density and amount of smoke in the air and ash produced by the fire. The thing about cold fronts and bush fires is they make the conditions for fire worse by pushing hot air in front of them. They have been blamed for the severity of the bush fires in Victoria in 2009, 1983 and 1939.


9

Right. We can make some estimates of the scale of the problem, but they will come with a healthy margin of error. If we assume that wood has a calorific value of 18.5 GJ/t (from the phyllis2 database) The area burned is 18.6 Mha (from Wikipedia here) The standing volume of material is circa 1500 m3/ha (an educated guess based on Eucalyptus values in Forest ...


6

Wildfires are mainly caused by humans (or their technology) and lightning. Lightning is the most prolific natural source. There really aren't many other sources in most areas, unless there is volcanic activity or a meteor strike as you mention. There are also occasional cases of wildfire when peat dries out. During a hot-dry summer, it can take several ...


6

Its just too wet there Generally, fires don't happen where it is wet. Here is a map of the fire regime in Pre-Columbian America: Northern New England gets practically no fires, with a fire frequency of every 200 years or longer. Southern New England sees more frequent fires, maybe ever 40 years, but those fires are typically understory only. For a ...


4

EDIT: As pointed out by Jean-Marie Prival and klanomath in the comments, I originally misread the specific heat of wood as per tonne, rather than per kilogram, and also used the wrong conversion between TWh and TJ. Here are my rough calculations, based on CO2-release estimates from NASA: 306 MtCO2 (wikipedia) Wood spec energy = 4.50 kWh/kg (...


3

This book is based on Australian experience, some of it may be relevant of North American wildfires. I read it ten years ago. Paul Collins, Burn - The Epic Story of Bushfire in Australia, Allen & Unwin, 2006, ISBN 9781741750539, ISBN 1 74175 053 9. Part 4, titled: The Great Fire Debates, has three chapters (9 to 11); 09 To burn or not to burn 10 ...


3

Forest fires, and natural disasters in general, get attention when they affect people. Bush fires outside of metropolitan Perth or far away from populated areas do not affect many people. Therefore, media attention is diverted elsewhere. This is not unique to WA: you have the same in NT, northern SA, and the west of eastern states. This is also not unique ...


2

It was a combination of thick smoke and pyrocumulus clouds. Possibly there might have been other types of cloud as well, Ash rising on the updraught may also have been a factor. I am informed that normal types of cloud sometimes made an appearance during the drought. Near-pitch darkness in daylight hours is also characteristic of volcanic eruptions, but I am ...


2

The same thing that typically cause them,.... Lightning. a very small percentage started by spontaneous combustion of dry fuel such as sawdust and leaves.


2

According to the NIFC report for 2016, there were approximately 1000 acres of wildfire burned in Massachusettes and Maine each. That is much smaller than California, which saw 560,000 acres burn in wildfires. There are wildfires in New England. They are just smaller in comparison to the rest of the country. This is largely due to the moisture of fuels ...


1

If you think how white smoke looks when it is rising elsewhere and you are looking at sunlight reflecting off it ... what you are then seeing, is some of the light that the folks who have that smoke between them and the sun are not getting. Smoke will also absorb a lot of sunlight (and re-radiate it as infra-red), especially if it's sooty black smoke rather ...


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