I grew up in Ohio and have lived my entire adult life in Florida.

I never really understood the California wildfires, and why when there were hundreds of firefighters, and helocopters, and air tankers, they could not be stopped.

Then someone said to me, "Think of a hurricane. But replace the rain with fire. That is what it is like during a California wildfire." And that made perfect sense.

I was reading about one today, and the article mentioned how the winds reached 70 mph. Then another thought occurred to me. If there was no fire, would the winds be that high in those areas as a normal part of late summer / early fall? Or does the fire, and the intense heat it gives off, actually create those winds? Which then drives the fire and creates a worsening circle of fire and wind?

There are winds ie the Santa Ana's that drive the fires. But the winds you speak of are largely fire driven.

quote:

Originally posted by holdem:
Or does the fire, and the intense heat it gives off, actually create those winds? Which then drives the fire and creates a worsening circle of fire and wind?

If I understand your question, then yes, that is a “firestorm.”

https://en.wikipedia.org/wiki/Firestorm

It’s believed that firestorms occurred in cities subject to massive incendiary raids on places like Dresden and Tokyo during World War II. Those fires were different from fires that start in one place and spread from there because they involved fires that were started almost simultaneously over large areas.

But winds will exist before the fire as well.

Several factors during CA fires in the Summer/Fall:
- no precipitation during these months, not a drop; Mediterranean climate which means very little humidity. The higher elevations in the Sierras will get mountain showers as clouds bunch up against the mountains but the rest of the state, that's it, nothing.

- The winds in the Fall are generated off the continent, most times of the year, our winds come off the Pacific blowing Eastward cooling the coastal areas making it a very attractive place to live; from the coast, you drive 10-15 miles inland and the temps will jump 25-30 degrees easily. Falling temperatures to the East and North pushes air westward & Southwest, as the air crosses over the Great Basin and Mojave the land heats the air; as the winds move westward, it gets forced into narrow land features, thus compressing and increasing its speed. So, you have parched vegetation, hot winds blowing...all that's needed is a spark to lite that vegetation.

- As the fuel burns, the wind continues to blow, feeding additional air raising the temperature and intensity of the fire, thus creating its own weather which can draw even more air into the furnace.

- As the wind blows, it carries burning embers, some as large as roofing shingles, across several miles, landing and creating spot fires either on the ground or, in the upper branches of trees. The wind continues to blow and the cycle repeats itself. Here in Napa valley, the main fire (Glass) was on the East side of the valley, winds carried embers across the valley and created two more fires (Boysen and Shady), winds fed the flames and carried the conflagration Westward into Eastern Santa Rosa.

- Geography plays a role as the mountains and smaller ranges are sharp and rugged, thus making it difficult for fire crews to get in and create the necessary fire lines and breaks. If the fire jumps those lines, its back to square one and those crews need to get repositioned, it's an exhausting process.

- Fire created weather does happen, fire tornados have been spotted, the largest was in '18 Carr Fire tearing up the outskirts of Redding. Smoke tornados also occur, look more like giant dust devils. Pyrocumulous clouds are another phenomena that can be seen over large fires.

- Fire fighting isn't a matter of pouring water on the flames, forest/wild fires are much too large to pump and pour water. Consider the fire in Paris of the Notre Dame cathedral, the fire brigade had to pump water from the Seine river because the existing fire hydrants couldn't provide enough water...this was a giant roof fire. Retardant is used to slow a fires advance but, fire lines created starve the fire of fuel thus burning out. The current Glass fire in Napa County is being directed into the fire scar of the LNU complex fire in August, less fuel to burn thus, the fire will be starved.

^^^^^^^

Years ago I worked for a firm that did software for aerial real-time wildfire mapping (I was on the business end but had quite a bit of exposure to the technical end). I think you have provided an excellent description.

I might add that the CA pro-enviro policies notably added to the "tinder" conditions that notably contributed to CA's worst fire season in history.

No, the fires don't create the winds that drive the fires. That would be more like a perpetual motion machine.

Fires do crease lifting action and release large quantities of moisture, both of which combine to create thunderstorms that do cause localized microbursts and winds, and do cause spot fires with lightening. That's not the mechanism that drives fires in general, and the winds that drive them are not the result of the fire. They're a contributing factor that supports the cause and propagation of the fire.

In the late 90's I fought fire in Florida (and for a time was the only heavy air tanker in the state, or that the state had ever used), at a time when the fuel moistures were equivalent to the mojave desert. The fuels looked green, but they burned easily and the fire behavior, flame length, rate of spread, and intensity was extreme.

Along with what others have noted, and to give a mind's visual; during the 2003 fire in Ramona (about 15 - 20 miles North-East of MCAS Miramar (whee I was living at the time), I was watching trees, 20' with 5"-8" trunks, bend first toward the southwest then back to the northeast with the wind. At the time I referred to it as "the fire is huffing."

This was not a light breeze. As the fire was (about) 5 miles from the base, the air was so dry the leaves on the trees became crunchy and were being stripped from the branches. At that five miles, embers were blowing across I-15 (think 7 lanes - in both directions - without a median) and starting spot fires on the west side of the freeway.

During this time of the year, and when the conditions are right, I sleep with my windows cracked and an ear on my wind chimes. Under the right conditions, people living eat of I-15 (and those just to west) may have as little as three hours to get out of a fire starts 25 miles to the east. and three hours is not that long when the fire starts at midnight.

Well, any fire could be considered a perpetual motion machine in that it will continue to burn as long as it has adequate proper fuel or nothing else interferes with the combustion. Both of those factors are of course why no fire is “perpetual,” but the right kind of fire can indeed create inflowing winds that influence the fire’s behavior. That behavior may not be that the fire is “driven” (however that’s defined), but the fire can be intensified by its own effects on the atmosphere.

I suspect we’re saying the same thing—or just talking about different things—but firestorms are considered real phenomena.

We used to run federal tankers out of Ramona, before everything transitioned to San Bernardino. SBD has long runways, Ramona is short, more of a one-way airport. Hemet, not far away, also short.

I remember sitting at the tanker base watching a DC-4 go out loaded to a fire; they rolled to the end of the runway and rotated hard, thanks to the fence and traffic just beyond the fence; the wingtip vortices pulled chunks out of the ground and threw them in the air. Add to it the pointy hills that stick up nearby and the inability to climb over them when taking off, and the cruddy visibility that so often settles in there, I never cared much to go into either one. The terrain in that area can be tricky, too.

The thing about fires and terrain is that the terrain accelerates the wind (venturi effect) and causes a lot of local changes. The terrain contributes to preheating of fuels and fuel concentrations, as well as being places where wind pushes the fire more, and makes it a lot harder to fight the fire.

Strong fires tend to draw airflow into the fire; it draws in from all sides, where the large pattern airflow is closer to calm, and vents upward; atmospheric stability and winds above the surface then play a big part in what the fire does, its movement, and behavior.

quote:

Originally posted by sigfreund:
Well, any fire could be considered a perpetual motion machine in that it will continue to burn as long as it has adequate proper fuel or nothing else interferes with the combustion. Both of those factors are of course why no fire is “perpetual,” but the right kind of fire can indeed create inflowing winds that influence the fire’s behavior. That behavior may not be that the fire is “driven” (however that’s defined), but the fire can be intensified by its own effects on the atmosphere.

I suspect we’re saying the same thing—or just talking about different things—but firestorms are considered real phenomena.

I get it. I've been a firefighter for a long time now. I've flown into and out of a lot of "firestorms," including many of the largest, and have fought them on the ground.

Firestorms are simply big fires; it's a media term. Back in the late 90's we had what the medial liked to call "firestorms" in Florida. The large fires we see presently are complex fires; they're multiple fires that burn together in what's termed a "complex," and when there are low fuel moistures, high large scale or local winds, atmospheric instability, good ventilation, ladder fuels, supporting terrain, and the proper conditions, they do burn hot and often, with extreme behavior. What might be a two or three foot flame length in grass becomes six or more feet, and small fires grow to two and three hundred foot flame lengths: extreme fire behavior. High rates of spread. Hotter, faster, more aggressive, spot farther, but still just a wildfire.

There's nothing perpetual about a wildfire. It perpetuates, but it's transfer of energy; fuels into gasses, into light and heat and release of moisutre, like any fire. One state traded for another. A fire can be self perpetuating to an extent, but is not a perpetual motion or energy machine (or cycle); it's constantly consuming, and there's always a cost for the energy it produces.

We chased a fire in Florida, northeast of Gainsville, I think, up to a small lake. We flanked the fire, running retardant along side it, and used the lake as a natural barrier where the fire stopped. Done. A few weeks later we were back on a fire on the other side of the lake: it burned up to the lake, and then burned under the lake, came up on the other side, and kept going. It burned in a pete bed beneath the body of water, and burned fairly rapidly. It's common for fires to go underground for a time, and sometimes come up some place else; we see it often...but never like that. It was a first for me, and everyone else I knew.

When theres a fire and there are strong winds, it's the winds driving the fire; fires do occasionally produce winds, but those winds feed back into the fire. It's how back fires work; the fires are ignited and the fire is drawn into itself, burning a band of black that acts as a fire break. The fires don't create winds that push outwards and cause themselves to grow.

Easy to explain, maybe hard to fathom. During the 2003 San Diego County Firestorm, I was on an evacuation detail as the fire was coming into our town. The fire/smoke was visible, at least a mile away with the wind blowing towards us. Then like something you have to see to believe, the inaccessible, granite boulder strewn mountain by our rally point started smoking, then fire erupted in several spots on this mountain. Very surreal to see it just CATCH on fire.

Why did it catch on fire?, it was the embers/debris a mile away being pushed by the wind and starting fires all along the way. This fire burned all the way to Miramar Air Station.

Wind, in particular Santa Ana winds are not your friend when there's a fire about.

The Santa Ana winds that go through SoCal are a very interesting thing.

The air comes flowing threw the high deserts out of Utah, across Nevada and becomes hot from the lack of humidity and high heat.

They then enter the CA high desert where they are funnel through the Cajon Pass area and Coachella Valley. As air is compressed, much like a jet engine, it picks up speed and then it blasts through the LA Basin, especially the Inland Empire, mountains and passes.

The air is hot and very dry and the velocity rivals Cat 1 and 2 velocities. A spark from a downed power line or a nut with an arson streak is all it takes. You can't really fight a fire like that in a traditional sense sense it's sending embers long distances in the air and firefighters are watching the fire leap frog.

You have to watch it in person to see just how destructive these wind driven fires are.

One thing to keep in mind is that tile and concrete tile roofs are not fireproof and in no way a fire barricade. If you live in the area and have watched a tiled house go up in flames, the reason is not complicated. The embers lodge under the eaves that are wooden. The eaves and rafter tails catch on file and the flames travel up under the roof in the attic area. Once the inside is weakened, the tiles, that weight about 9-12 lbs. per square foot collapse from the peak.

You have to live here to see flames destroy a house, skip the next couple because of winds and then repeat the pattern.

quote:

Originally posted by Flashlightboy:. . . You have to live here to see flames destroy a house, skip the next couple because of winds and then repeat the pattern.

I have been through tornado sirens, but never a tornado. I understand they can have the same pattern you described above. One house totally destroyed, the house next to it almost untouched. (I did have a friend in the Joplin MO tornado, the roof of a church was totally ripped off, but loose papers on the office desks were not disturbed.)

Corsair summed it up well. We got zero rain in February of this year, which is typically one of our wetter months. We’re going into our sixth month without measurable rain, not counting a few showers that came with a freak two day lightning storm in August.

The Diablo winds pushing the 2017 Tubbs/Nuns/Atlas fires were 50 plus mph sustained with gusts measured to 80. Combined with single digit relative humidity, the entire region turns into a tinderbox.

I saw cars in Coffey Park that were flipped on their roofs and pushed into the park itself by fire generated winds.

The Glass fire threw embers across the Napa Valley and created spot fires that covered 12 miles to Santa Rosa/Sonoma Valley in about 2 hours.

The Hennessy Fire in August did the same thing. People in Vacaville went to bed not worrying about a fire 18 miles away, and woke up to evacuation sirens at 0300 hours.

One thing that is really hard to get your head around if you're from the East is the lack of moisture. I live in Colorado and we haven't had a drop of rain at my house in over 10 weeks. Well, we did get a freak snowstorm in Sept, but that was it. The dryness is somewhat normal. It is dry, dry, dry as a bone.

For example, Denver gets 12" of precipitation on average per year. Much of that is in the Spring. I grew up in Northern NJ and I think the average rainfall is around 35" - 40" or so per year. We get tons and tons of cloudless, sunny days with very little humidity.

Funny, there are signs everywhere in Colorado....Welcome to Colorful Colorado. I always thought that was funny because Colorado is very brown compared to the East. I know you mentioned California, but Colorado is very similar, climate wise.

Just finishing my 2nd read about the ‘Peshtigo Fire’ of 1871. It was a massive, very fast moving fire moving through woods & towns. It happened the same days as the ‘great Chicago Fire’, with many more causalities.

https://en.wikipedia.org/wiki/Peshtigo_fire

I think in many areas of CA you have extremely dry brush, tinder, with trees. When wind is added plus terrain, very hard to fight effectively. I think there’s more going on beyond poor ‘forest management’. The natural cycle of drying out late Summer is one.

quote:

Originally posted by sourdough44:
I think in many areas of CA you have extremely dry brush, tinder, with trees. When wind is added plus terrain, very hard to fight effectively. I think there’s more going on beyond poor ‘forest management’. The natural cycle of drying out late Summer is one.

There is more going on than poor forest management. There are more and more people moving into the country and not even considering, much less taking responsibility for providing defensible space around their homes. There are environmental policies that make it difficult to do anything even if one does decide to plan ahead. The stupidity in CA is absolutely rampant.

I've commented on the Peshtigo and numerous other fires here before; while of interest historically, they bear no comparison to the current situation. The ability to detect and combat them, the resources available, the incident command system and the fire infrastructure, the population, communications, transportation, and even the continuity of the fuels over such a large area were so vastly different as to render it what it was; a fire from another era, another place in time. No comparison at all.

This isn't poor forest management. That's a bullshit copout excuse of massive proportions that speaks to ignorance of the fires, the root causes, and of forest management itself.

California has had a long, extended drought, and is frequently in a drought condition. The topography of the state differs from the rest of the mountain west in its relationship to the ocean, and winds, and weather. The population continues to grow, thrust more and more into the urban interface between wildland and suburbia, with the suburbia more and more adequate to support fire passage due to vegetation and fuels.

California is subject to high wind events on a regular basis. California is largely mountainous, with numerous national forests. These forests dry out over extended drought seasons; one or two years of good moisure do not make up for the years of no moisture, and the high rate of water usage taxes what water there is, resulting in frequent water rationing that's been going on there for decades.

I listen to conjecture about california's fire response, but it's never by people who actually respond to fires there, so as one who has and does, let me say that those who complain about the adequacy of the fire response in Region 5 (California) are way off base and have no idea what they're talking about, as are those who make idiotic, uninformed political statements placing blame on forest management. It's utter bullshit.

I'll tell you how extreme it gets. Many places in the mountain west, I've arrived at a fire as the only response, and there may be an engine crew enroute with 3-4 persons on board. I've been on hundreds of fires in which a small hand crew was the only resource to handle a thousand acres, at that moment, along with a very limited response in the air.

In California, I was over a fire and got a call for a smoke report, property at risk, with burn injuries. All the magic words. I bumped over to the coordinates. Within minutes, we had fifteen engines enroute, pulled off a nearby burn, along with multiple ambulances. Five helicopters arrived, and over a thousand personal were dispatched. Five heavy tankers and another ten from nearby were re-directed. I arrived first on scene.

The fire was at one end of a small, narrow resorvoir, with minimal vegetation. At one end were two clumps of trees, each over a small one-family camp ground. From one of the clumps, rose a thin column of smoke. I arrived overhead in full cruise and rolled into a steep turn and began setting up. The first ground units were nearly on scene, all coming up a one-way two-track dirt road which was complicated with opposite private vehicle traffic.

Personnel were able to reach the fire coordinates, where they found a camp fire burning in a fire pit, producing smoke, and a teenage girl who fell asleep in the sun and had a sun burn. Fifteen air tankers, five helicopters (and a few more enroute), air attack, leads, fifteen engines, a thousand additional HotShots, Flame-in-goes, helittack crews, VFD (volunteer) personnel, engine crews, etc, and multiple ambulances and medical personnel...for a camp fire and a girl with a sunburn. Meanwhile we had a 30,000 acre fire to get back to.

California doesn't fuck around with fire reports. Ever. They do everything on run cards; on a given day, for a given set of conditions, if a fire report is had, everything on the run card gets dispatched. California averages about eight to one on false alerts; I lost track of the number of times I responded for a fire and then stood down...but they spool everything up, every time, and they're deadly serious about it. Nowhere else in the country operates like that, or with the complexity; California is like a separate country when it comes to fire. They even use their own radio system, and it too, is far more complex than the rest of the country.

I have arrived at a single tree fire to see a thousand personnel converging. I kid not.

It's tough to see homes lost, lives lost. It is. People want answers. People want to place blame. I once responded in a brush truck to a fire and was prevented from getting out of the truck, by the chief of police, who leaned in the window and told me it was my fault (fire depts fault) for the fire, because we hadn't cleaned up all the brush in town, and done controlled burns. Same idiot once pulled over our fire chief for speeding, who was lights and sirens on the way to a fire. Dumbass. But that bullshit mentality isn't any different than those saying that whats going on now is poor forest management (and poor response). It's neither. It's a fucking wildfire.

We also see fires continue to burn with greater intensity each year, a trend that's been going on for a long time. That's also not a management issue, but has everything to do with the physics of fire behavior and the principles and laws that govern it.

Build your house in an urban interface, or build it in the forest, it will burn. Maybe not today, maybe not tomorrow. but it will burn. Bank on it.

I was at Yarnell a few years ago, a place in Arizona that burned, where we lost 19 firefighters in a single burnover, following a blow up caused by a thunderstorm (NOT by winds created by a fire...). The entire hotshot crew, save one, was moving down from a safe zone in the black, to do structure protection, where they'd been ordered to go. They were caught when the fire reversed direction with 70 mph winds in outflow from a massive thunderstorm that moved in from the north. I was there.

Following that, policy changes were made that structures do not justify the cost to life, but firefighters continue to die fighting fires that needn't be, largely to protect people and structures in places that carry a certain risk of burning. Again, build your home in the wildland interface, those places where your home is among the trees and grasses and fuels, and at some point in time, a fire will take it. There aren't enough personnel or dollars to vacuum up every bit of ladder fuel, duff, and prune every tree in every forest. It's an idiotic idea, rooted in extreme ignorance. There are a hell of a lot of home owners who can do a lot more to make their own property more defensible and less likely to burn, and that's the place where it needs to start.

Not like the guy on the news a few nights ago who complained that his home burned down, he built it again in the same spot, it burned down again, and now he wasn't sure if he wanted to build it one more time. Like Homer...Doh, doh, doh, doh, doh, doh...how many times does it take, to learn?

quote:

Originally posted by sns3guppy:


We chased a fire in Florida, northeast of Gainsville, I think, up to a small lake. We flanked the fire, running retardant along side it, and used the lake as a natural barrier where the fire stopped. Done. A few weeks later we were back on a fire on the other side of the lake: it burned up to the lake, and then burned under the lake, came up on the other side, and kept going. It burned in a pete bed beneath the body of water, and burned fairly rapidly. It's common for fires to go underground for a time, and sometimes come up some place else; we see it often...but never like that. It was a first for me, and everyone else I knew.

My brother's family and another had a bonfire one night. They put it out (or so they thought) and went to bed in the two cabins nearby. Turns out that an old and large tree root was near the burn pit. It smoldered and burned underground and set the other family's cabin on fire at 3 or 4 a.m. Little girl died in the fire.

First time I had heard of that, but I am now more careful than ever about putting out campfires and such....

Much of California gets an inch or less of rain a year. You're used to storms that drop an inch an hour, frequently.

California is a tinderbox. Add the winds and horrid forest management and you have the perfect cocktail.

quote:

Originally posted by SBrooks:
My brother's family and another had a bonfire one night. They put it out (or so they thought) and went to bed in the two cabins nearby. Turns out that an old and large tree root was near the burn pit. It smoldered and burned underground and set the other family's cabin on fire at 3 or 4 a.m. Little girl died in the fire.

First time I had heard of that, but I am now more careful than ever about putting out campfires and such....

Unfortunately, fires going underground are a very common occurrence, from lightning to portions of downed trees, to roots, to peat. I chased a fire a few years ago that disappeared and kept popping up; turned out it was on top of a collapsing section of old west mine, and was too dangerous to put personnel on the mountainside. It was retardant or nothing, and it kept going down into the mine.

Fires should NEVER be left unattended.

Fires routinely pop up a week or two after lightning; they've been burning below ground and smoldering until the necessary conditions occur, and the fire takes off.

The USFS uses the term "dead-out." It refers to "drowning" a camp fire. Even so, the fire materials should be turned over and where possible, broken open, because burned surfaces will cause water to beat off them, and the water doesn't penetrate. (It's for that reason that surfactants and foams are used, that break water tension and allow water to penetrate into burning fuels). The old counsel about not putting an extinguished match in the trash until it's cold enough to hold in your fingertips also applies to camp fires. If there's any heat at all, it's not out and it could come back. I've fought fires that were caused by welding; the welding was over, the equipment put away, the welder left, but the fire took off. Fireworks. Tannerite. Shooting. Mining. Train tracks. Car exhausts. Lightning, etc. In many cases, the fire occurred later than the ignition event was believed over...even a woman burning her used toilet paper once. The fire tee shirt produced at the fire camp was a naked woman running away holding burning toilet paper.

California's August Complex just achieved "gigafire" status, signifying 1,000,000+ acres.