The amount/size of wildfires you guys/gals experience out West is pretty staggering. If you’ve been near one (or even say 100 miles away), do those large wildfires act as their own weather? Say you’re at home in your backyard, and the Utah fire is 60 miles away from the edge of it’s perimeter. Do you still have an increase in local temps because of the massive fire? If the winds are right, will the smoke cause beathing problems for people?
Are those wildfires large enough that they suck all the oxygen out of the area increasing the winds etc. like a firestorm ala Dresden/Tokyo?
With the super high temperatures + out of control wildfires = must be awful.
I’ve been within 100 miles of a wildfire on numerous occasions and you don’t notice except for the news reports on TV. Of course I generally have the Cascade Range between me and the flames. But I think you have a somewhat exagerated sense of what a wildfire is. You seem to be describing some kind of Sci-Fi original movie starring Dean Cain and Casper Van Dien.
You won’t see Dresden/Tokyo firestorms in the wild. They were the largest fires ever, not just manmade, and not even volcanos have created fires like that in known history.
So while wildfires are scary and dangerous if you’re close, they’re not on that level. A firestorm large enough to suck up oxygen is hard to create (needing a dense collection of flamable material - ie a city - and a large number of fires. Dresden took 1500+ planes)
I’m sure people with respiratory problems get in trouble if they’re downwind from a brushfire.
Well, I’ve never been near one, so that is why I’m asking. And yes, my view of them is probably influenced by my college term papers on the Tokyo and Dresden firebombings.
But at any rate, I do wonder how far out the heat and pollution radiates and if it changes the local weather patterns.
There have been a couple times in the last ten years or so that fires have been large and/or close enough to produce a smoky haze in the city. There was a strong smoky smell, but no real breathing problems for normal people, though warnings were issued for the elderly and people with respiratory problems. No obvious change in heat or weather.
I can’t remember if any of those fires were really that close though, as the smoke can drift quite a ways.
This year’s south Georgia fires were hundreds of miles away from my home in north Atlanta, but it was bad enough that you could smell it and in some cases a haze – like fog – would cover things and badly reduce visibility. It would feel like an overcast day with fog, but it was all smoke.
In Macon, which was closer to the fires, the smoke was bad enough to impede visibility and make driving dangerous, like heavy, heavy fog.
A “firestorm” created from a wildfire is fairly localized and the spread/rapidity really depends on terrain, localized weather conditions, fuel state, etc. If everything is right, you can certainly have an event that is Dresden-sized, but it all depends on really how you define something like Dresden in time, space, and and energy in comparison to some of the big firestorm events around wildfires.
For instance, a wildfire can move blindingly fast, rolling up the a slope where its speed, rapidity, access to fuels, and the fact that it feeds itself from its own heat and spread at something like 60-80mph. That’s not low-lying fire either, that’s tall rolling flames.
Yes, but even in Dresden, the firestorm was localized to the city. Five miles away from the city you wouldn’t have felt any warmer. The heat all goes UP, see.
Except wind can drive a fire in particular directions (not to mention it can generate its own winds), which can create a “firestorm” of a different type. Heat goes up, fire doesn’t necessarily have to.
In Dresden there was flames 6-8 kilometers up. Observation planes going to close was tossed upwards a kilomter in an instant others lost wings due to upwinds. Witnesses described bricks and roofs and even humans sucked in by the winds. Ponds and lakes evaporated. All oxygen was sucked out of the burning area and later rescue workers would find shelters with thousands unburned but suffocated people.
No brushfire is as bad and while the term firestorm is used, it’s a different beast. And yes they move pretty fast, but they’re still localized. You don’t have to be that far away not to feel any heat - if we’re talking miles as in JPs question, you won’t feel it. Allthough smoke might impair visibility.
The rule of thumb I learned as a firefigther was that ‘fire moves upwards in seconds, sideways in minutes and downwards in hours’
I’ve been near several wildfires. The most memorable was in Mesa Verde (SW Colorado, a fantastic Anasazi ruin). The main road out of the park was closed moments before I reached the roadblocks so that tanker planes could do drops on a fast-moving blaze. Watching the pilots maneuver through jet black smoke just above the tree-covered hills about 100 yards away was quite an experience.
I’ve also been near some much larger and far more damaging blazes in California–one in Simi Valley rained ash on my house in Oxnard, 20 some miles away. Air quality was terrible and the lighting was really weird, but there were no weather effects.
When I lived in Southern Oregon, there was a nasty fire one year that caused some bad smoke, enough so that a lot of people ended up going to the hospital.
Well the term firestorm is used to describe a fire so intense that it creates its own wind/weather system, thereby feeding the fire and usually causing rapid fire movement and growth. That’s the usual use of the term; people would call something like the Yellowstone fires a firestorm, where all it had been was a series of human- and lightning-caused fire zones where low humidity, wind, terrain and other factors conspired to make them extremely hard to control.
More appropriately certain events such as Peshtigo, Storm King Mountain, Tokyo and Dresden are given that label, which make a lot more sense.
Back to jpinard’s question as I fear we are getting slightly off-topic, I doubt that 60 miles away you would be seriously affected, but it’s hard to say–it depends on the fuels involved, particulate matter of the smoke, wind direction and your vulnerability to bad air. When I was in Wenatchee last year there wasn’t any fires for 50 miles or so (the big fires of Washington in '06 were north of there) and one day could be clear, the next it would be nasty hazy. Of course, this year, the fires are right on top of the town and right near where I stood at a friend’s house. You definitely wouldn’t feel a temperature or weather change (I don’t think) at 50-60 miles.
If you’re within 20 you may see thick clouds of smoke and it could get quite thick, affecting breathing and the like. You probably wouldn’t feel any temperature changes, though wind could shift without warning.
Once you’re around 5 miles there might be some residual increase from heat, but all of the other effects could be magnified. You may run into some embers and you’re in some slight danger. Convection columns may produce huge amounts of smoke and ash and you could be in danger of getting struck by lightning from pyrocumulus clouds.
At a mile or so you may or may not feel a noticeable heat increase (depends on where the fire is, wind direction and if the fire is fronting or crowning in your general direction), and again the other effects will be up somewhat. You’re definitely in a lot more danger–embers can easily start spot fires and if it blows or firestorms up you’ll have very little warning (depending on the terrain and other conditions mentioned previously). Definitely not recommended if you have trouble breathing normally in bad air. Visibility could be shortened a lot and depending on the wind you could be in thick, black smoke or none at all. Unless you’re a firefighter or want to defend your property I wouldn’t really recommend it (though of course if you’re a thrill-seeker…)
My friend was driving from Mammoth to San Diego on Sunday and had to take a huge detour through Vegas because a big section of the 395 was shut down due to fire.
Hasn’t had any direct impact on me down here in SoCal.
A couple of years ago I got a few days off of work because of big fires in San Diego that caused so much smoke build-up in the area where I worked (Sorrento Valley) that it was unpleasant and borderline unsafe to breathe the air.
Oh, I agree with everything. Firestorm is also what happens in some wildfires - I was just commenting on JPs comparisson with Dresden/Tokyo which is an alltogether different (rare) beast.
While I’ve never been in a huge wildfire like you or the Australians get, I’ve been involved in smaller ones.
While the smoke nearby is bad and certainly unhealthy, the normal wildfire isn’t sucking up oxygen, so you can still breathe without full breathing apparatus on - which is why - I guess - you don’t see smokejumpers jumping with full smokediving gear (another 16+ kilos to an allready heavy gear).
So unless there’s a chemical fire in combination or you suffer from ashtma, you can still breathe close to the wildfire. Not that doing so is healthy or easy/pleasant.
And while the heat would seem unbearable hot a few meters from the fire, that effect drops off quickly and I’d say that 100 yards from a big fire you’d only feel as if you’re getting a sunburn. Miles away? Nothing.
We used to train making a “road” inside a burning city drenching each other with our hoses to get people out of shelters before they suffocated. A technique developed by German firefighters in WWII. That was hot… but you really don’t have to walk far for the heat to dissapear.
For anyone who’s curious, I took some photos of areas which burned several years ago during my vacation this year in Central Oregon at the end of June. I’ve posted them as part of an online album here: http://picasaweb.google.com/brad.grenz/BlackButte2007
I think the prevailing wisdom, around here anyway, is to let the forest recover naturally. But I’m not sure how much of what would be suitable for salvage.
Here in Santa Maria we get at least one a year within a 100 miles. If the wind is blowing the wrong direction air quality gets pretty bad. Other than that its not ussually that big a deal.
As for why they happen? My personal opinion is that, The environmentalists have made it so much of a pain in the ass to get a permit to clear brush from your own property that it becomes not worth trying to do untill it gets to the point where a small spark will burn everything for miles.
