how come wildfire embers can travel miles and start new fires, whereas fire pits and bbqs can be 10’ from a house?
In: Other
> Charcoal or other solid-fueled grills were involved in 1,300 home fires per year.
People set fire to their own homes [all the time](https://www.nfpa.org/News-and-Research/Data-research-and-tools/US-Fire-Problem/Home-Grill-Fires)
For one thing, anyone using a BBQ grill or fire pit at their house also has immediate access to water. So if an ember were to land on or near the house the homeowner would be able to extinguish it immediately. Heck, usually you can just stomp it out with your shoe.
But another reason is the draft caused by the fire itself. Fires create wind. The bigger the fire, the more powerful the wind. The fire pit in the back yard is not nearly big enough to send an ember traveling for miles. In fact, small fires like you would have in a fire pit send very few embers into the air, and they nearly always go out immediately when they land.
Finally, there usually isn’t as much burnable material in the area immediately around a person’s house. Lawns don’t burn so well. Barkmulch actually doesn’t burn all that great, either. So when an ember does land on the ground near the house, it is very unlikely that it will be able to actually start a fire. And, again, if it does – you have water.
But despite all of that there is always some small risk with BBQ grills and fire pits, which is why when it has been especially hot and dry, the local authorities may put fire restrictions in place.
The fires are huge and they [cause enormous amounts of wind](https://wildfiretoday.com/2019/06/17/360-degree-video-inside-a-forest-fire/) as they superheat the air. The embers that are carried away are not just teeny tiny little bits of barely glowing ash, but large enough chunks of bark that they can smolder for a couple of minutes.
When you have a small fire pit, when an ember lifts up, it will quickly cool down in the cooler air surrounding the fire – so by the time the ember had blown any distance from the fire it will have rapidly cooled down in the normal air to the point it is unlikely to catch things on fire.
When you have a forest fire however, the fire is huge, and is quickly heating up all of the surrounding air. So when an ember lifts up, it cannot drift out into the cooler air and cool down itself, because there is no cool air there – so it will stay heated by the volume of hot air coming off the fire. This means it will travel a lot further before it escapes the heat of the fire and starts to cool down to a safe temperature.
It is worth mentioning however that all fires have the potential to be very dangerous – the embers coming off a garden fire pit are still more than capable of starting fires nearby, as evidence by the amount of fires that are caused by people being careless with fire pits and campfires.
Latest Answers