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On a hot day on July 26, 2018, a record high temperature of 113 degrees baked Eric Knapp of Redding, California's Sacramento Valley, toiling in an air-conditioned government office . After get off work, he plans to have dinner with his wife, 3-year-old daughter, and some family and friends. Knapp is slim, fair-skinned, with a gentle smile, and is a research ecologist with the U.S. Forest Service. He clearly knew that three days ago, in the coastal mountains west of the town, a fire started. At that time, the trailer had a flat tire and the metal rim scraped the asphalt, sending sparks into the dry brush.

Like a sea of ​​people

, This is the so-called "Karl's Fire". When it first burned, it was a broad and shallow flame. It moved slowly, like an infantry battalion marching side by side, leaving charred grass and lightly charred trees. . A typical feature of Carr Fire is also that it moves according to wind, ground slope and flammable fuel indications-south-southeast around the lake, and then remote on the hills, partly due to rising heat. On that particular morning, a fire rose above Redding, with northwest wind behind it, climbing down the mountain.

November 2020.

Knapp ended his day. His friend Talitha Derksen is a wildlife biologist. His daughter is about the same age as Knapp himself. He sent a text message saying she Neighbors may have to evacuate. One of the agencies responsible for the judgment task, the California Forestry and Fire Department (also known as CalFire) is one of the largest and most effective field fire protection organizations in the world. CalFire's evacuation recommendations are based on predictions of where and how fast the flame forward will move next. That day, the fire seemed likely to reach a zone called Land Park on the floor of the Sacramento Valley, about a mile northwest of Dirksen’s home.

Knapp and the others changed their plans: they would meet at Dirksen's house, order pizza, and help her get ready to leave, just in case. Knapp stopped at his house to pick up the fireproof Nomex clothes. When he went to Derksen's house, he considered going to the office again to pick up his helmet and emergency fire shed (a small fire-resistant tent), but he decided that it was unlikely to need them.

When he turned to the streets of Derksen, the front of the flame was a few miles away, covered by trees, but Knapp could see the thick smoke standing upright and the high plume turning the orange into the sun. When he arrived at Derksen's house, she was already packing her luggage. To make sure he knew what they were dealing with, Knapp jogged the nearby Sacramento River Trail to enjoy the scenery. On the remote river bank, Upriver can see red flames burning gray pines and dwarf oak trees.

Knapp was taking the picture when he noticed something strange: the wind he was standing on blew into the fire from the south, but the front of the flame was still moving in the opposite direction, which was driven by the northwest deflection behind it. Then he saw another thing: the part of the plume was spinning in different directions, as if it was starting to spin.

Knapp knew that this might herald a once rare and dangerous phenomenon called plume fire, in which the convective column on which the fire itself rises becomes hot enough and large enough that

The fire can burn hotter in some way, and spread quickly without warning, enough to trap people fleeing.

When Knapp ran back, he walked past the neighbors, suggesting that they turn around. However, even he does not know how many of these dangers are. When Dirksen left, Knapp and others used hoses to flush the roof and rain gutters in the house, and cleaned up flammable items such as cardboard boxes and lawn furniture. Knapp was the last person there, sprinkling water on the fence and yard.

Even when Knapp shook the faucet, the swirling smoke he saw was still accelerating rapidly, turning Carr Fire’s huge low-level plume into the largest tornado ever observed, spinning The vortex is 17,000 feet high and spins at a speed of 143 mph. The destructive power of the EF-3 tornado, which will wipe out entire towns in Oklahoma.

When Knapp was spraying water smoothly around Derksen's house, the tornado-all the smoke in the air was hidden under him-traversed the Sacramento River, landed in the land park, and intercepted the high-voltage power line. , He uprooted trees, wrapped surrounding electric poles with steel pipes, destroyed hundreds of houses, ignited them, shredded them, and threw their burning debris to the height of commercial jetliners.

When all the windows burst open, CalFire captain Shawn Raley was standing not far from Knapp, evacuating a woman and her daughter from the truck and showering them with broken glass. Nearby, a 37-year-old fire inspector named JJ Stoke made a broadcast on Mayday’s broadcast, where a tornado lifted its 5,000-pound Ford F-150 from the asphalt and repeatedly flipped it over to Buena. He was blown up while on the Ventura Boulevard. When the window was also broken, three other CalFire workers were driving a bulldozer on the same boulevard. One of the 25-ton cars was dumped and fell on a truck driven by a retired policeman. Then the policeman jumped out of the car and squatted behind the blade of the bulldozer while his truck caught fire.

That's about when the burning debris inhaled in the Carr Fire smoke floats out of the updraft column and enters what the fire meteorologist calls the settling zone, which is exactly what it sounds like. Knapp can't see this situation. It was tens of thousands of feet above him. He also couldn't see the burning debris of houses and trees blowing down like a bomb, hitting the roof and igniting dozens of houses. When Knapp looked up at the black whirling darkness above his head, he still thought that Carl Fire was advancing with the slow predictability of a typical shallow flame front, watching the embers fall on the bark chips on which he was standing and ignite them. At the same time, the ground under his feet was burning, and Knapp felt a stronger heat pulse.

The 2018 fire season in California became the most destructive fire ever-this title lasted for less than 20 months, when the name was not only replaced by the 2020 fire season, but only by it

At the end of summer 2020.

The tornado and the fire a few weeks later eventually destroyed more than 1,000 houses and buildings, killed 8 people and scorched nearly 250,000 acres. However, this is neither the largest fire in California in 2018, nor the most destructive fire, nor even the only fire that has manifested in an unusual way. The Mendocino integrated fire, about 100 miles south of Carna, started on the second day when Knapp was unknowingly hovering under the tornado. It was also driven by a short plume and eventually burned nearly 460,000 acres. This was the largest California wildfire ever recorded at the time. In early November, the Woolsey Fire near Malibu destroyed 1,643 buildings and at the same time forcefully destroyed trees and electrical wires by another fire tornado. This

Also in November, 70,000 acres were burned within 24 hours (about one second) and caused a city fire, destroying more than 18,000 buildings and killing 85 people, most of which occurred in the town of Paradise Billions of dollars in revenue. Insurance claims and bankrupted PG&E, the state’s largest utility company.

By the end of the California fire season in 2018, it had burned more than 1.6 million acres, making it the most destructive land ever-this title has been maintained for less than 20 months, but by the 2020 fire season it has been more than just

At the end of the summer of 2020, an estimated 3 million acres have been burned. But this is not the really worrying part. As far as Western wildfires are concerned, the total area burned is far less important than the ever-changing violence of our most extreme fires. It seems that we have passed a certain degree of climate and fire sources and entered an era of uncontrollable fires.

"Not only is the size and severity of fire alarms increasing, but the nature of the fire is also changing," said David Saah, director of Pyregence, who is responsible for the fire science laboratory and researchers working on this issue. Cooperative team. More worryingly, given that fire trends are more catastrophic than anything we have seen so far: the physical principles of large-scale wildfires are still so poorly understood that fire modeling software is often unable to effectively predict the next fire. Where they happen, not to mention how they will unfold once completed. As Saah said, if there is any good news, it is that "the science of a lot of these things is under development."

Eric Knapp worked for the U.S. Forest Service in Northern California for 16 years.

After the Carl fire, on a bright day in June 2019, a large-chin fire science researcher at the University of California, Brandon Collins (Brandon Collins), drove a white pickup along the cedar-scented mountain road into Blow. Jeter Experimental Forest, which has 4,000 one-acre university properties near Lake Tahoe, where he studies the impact of forest management practices on wildfire risk. All these practices begin with the inevitable fact that California is flammable. It is difficult for us modern people to accept-limited by our Smokey Bear-but in the western United States, fires are natural and inevitable, just like the floods in the Mississippi River and the hurricanes in Florida. Not only are fires guaranteed by climate and ecology; they are also vital to the health of many ecosystems. In fact, in the 20th century, there were far fewer fires in the West than in the West today, and this should be properly regarded as an unnatural anomaly. A study showed that before this, especially before the Anglo-American conquest, California's annual wildfires burned about 6 million to 13 million acres, far exceeding the current record level.

However, most of the frequent fires that have occurred in the past are different in key ways: they burned with a shallow front, just like the early days of the Carl Fire, they passed through grass, pine chips, and fallen branches-so-called surface fuel-rather than like Our biggest fire today cut down the entire tree into fire, from the canopy to the canopy. Those frequent ground fires usually keep the total fuel load low, so that each subsequent fire can only do the same thing-burn down the forest without damaging mature trees. Over time, this continuous forest of conifers, oaks and Madrones is widely distributed on carpets of grass and shrubs, which in turn provides excellent pasture for the deer.

For thousands of years, the entire western United States has managed land to achieve this result-so successful that it was adopted by British and American ranchers and even loggers in the late 19th century.

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Collins showed me the situation and parked the truck in an area in Blodget Forest, which had been managed in the old way for 16 years and opened fire regularly. From worries about desolate deserts or dark caves to the calmness of tropical coves, our responses to the landscape vary. I can report that when the forest is allowed to burn in its own way, it feels great. The sun-dappled galleries are overgrown with huge sugar pine, Douglas fir and black oak shaded grass-like ground, although avoiding the weather, But it is open enough to move freely.

The Forest Service currently controls approximately 20 million acres of California, and almost completely ended this land management since the establishment of the agency in 1905. -Not realizing that wildfires play a positive role in ecology, the Forest Service learned to extinguish all flames in each forest as quickly as possible. The erroneous thinking of this method became obvious to the institution itself in the 1940s, when researchers at the institution began to recognize the fact that the longer the forest did not light the fire, the more fuel accumulated and the more serious the fire. .

This insight made it part of the official forest service policy in the 1970s, encouraging regional employees to use deliberately controlled burns as a means of reducing fuel load. By then, unfortunately, the wood and paper companies had already burned down, did not like the smoky air, and so did the civilians who enjoyed entertainment in the national forest and thought of fire in a purely destructive way. Coupled with the issue of legal liability (who is responsible for compensation for the loss of private property caused by designated incineration on public land?), all of this makes Forest Service officials reluctant to make any specific regulations for burning, which is understandable. The private property owners who controlled the other 13 million acres of forest in California (and still do) have no incentive to ignite their land, let alone tolerate their neighbors. At the same time, CalFire’s mission is to respond to every fire on 31 million acres of non-federal land within state boundaries, and it has almost no fuel management department compared to the Forest Service. CalFire’s direct responsibility is to spend more than $2 billion a year to operate more than 700 fire trucks and 75 aircraft to quickly extinguish all fires-this work has performed well in approximately 6,400 wild fires each year.

California Fire Department Chief Brian Estes is only responsible for fire protection operations in three of the 58 counties in California. He said: “We have 400 to 500 fires every year. In the hot summer, Five or six times a day, and in most cases you won’t see it. Whenever I have a 911 dispatched to a vegetation fire (such as a grass fire on someone’s lawn), "You will get 7 engines, 1 Battalion commander, 2 bulldozers, 2 aerial tankers, 1 airstrike and two-handed crew. They will roll out the barn. But if you do this for a hundred years, and you don’t allow people to do the prescribed firefighting , Then the fuel will only become denser and denser."

Collins showed us a graphical example of our next stop, a forest that has not been cut down or burned for more than 100 years. The trees are tightly packed between big and old trees, not only piled with ground fuel such as pine oil and leaves, but also piled with so-called ladder fuel, which helps the ground fire to jump to the crown of the tree and spread the large branches and shrubs. The clump rose faster. The forest was also frightening intuitively: dark, gloomy, labyrinthine and spongy, an ancient fairy tale nightmare forest.

It seems to be very flammable, even if the forest is poorly managed, like that patch, it has been burning in a historical manner until recently, and the severity of the forest area is low. As a result, the entire field of wildfire science-including the model tools used by firefighters to determine life and death and the society's own structure in fire-prone areas-is based on this fire behavior. The core mathematics of this science can be traced back to the early 1970s, when a forest service researcher named Richard Rothermel used small laboratory fires to generate equations expressing the relationship between wind speed, ground slope, and fire spread speed. Rothermel knows that his method is only suitable for light-surface-fueled wildfires like his laboratory, and cannot capture what happens when the fire enters the treetops and jumps from crown to crown. But these so-called Rothermel diffusion equations are applicable to so many wildfires that the Forestry Bureau quickly developed paper and pencil methods for firefighters to insert wind and slope figures and make reasonable guesses about the speed and direction of the fire. . It may spread along a single headline in a straight line. In the end, the modeling framework ran on a bulky supercomputer and then on a handheld calculator. In the early 1990s, PC-based software finally enabled firefighters to predict the spread of fire in two dimensions on a map.

The software was created by forest service scientist Mark Finney and was severely restricted due to lack of maps and fire fuel data. In other words, if you cannot load topographic maps and vegetation data into the fire that needs to be extinguished, it is not very useful. However, over time, other researchers edited these data sets themselves and shared them with each other, until 2009, they were available throughout the United States. Finney's software can now predict the spread of light-weight ground fuel fires well, so it has become an industry standard and is used thousands of times a year by firefighters across the country. Versions eager to simulate future fires are also used by land managers eager to prevent them from happening.

However, as early as 1994, Finney could see that modern modeling frameworks have more serious limitations. That year in central Washington State, a large and unusual fire was called the Tyee Creek Fire, and its behavior was completely beyond the scope of the Finney model. Finney said that instead of burning with a shallow flame front that changes with the wind and terrain, it is better to say "the fire spreads at almost the same rate in three directions every afternoon"-like the wind blows outwards to some extent. 360 degrees is the same. The center of fire.

The Tiy Creek Fire also kept its huge central area burning for several days. This is a speculative phenomenon known as a large-scale fire. Finney said: “It just swells up and releases huge feathers, and then expands, expands, and expands every day.” “I remember thinking,'Wow, this is beyond the scope of what we can model now, even It’s silly to try.’”

Finney realized that any modification to the Rothermel diffusion equation would not enable them to explain fires like Tyee Creek. They are not only developed around small laboratory furnaces, but 20 years of experience using them have focused on shallow flame fronts moving quickly through light fuels, without considering the slow-burning heavy fuels ignited along the way, and the feedback between ground fires It is much less. And direct atmosphere. In other words, as Finney recalled saying to a colleague at the time, “The truth is, we don’t know how these things work.”

In order to solve this problem, since the early 2000s, Finney returned to the original principle without making any assumptions. He ignited a new experimental fire at a research station in Missoula, Montana, and re-examined some basic questions, such as whether wildfires were caused by simple heat radiation (the traditional knowledge at the time) or by direct contact with the flame. Diffuse.

"This is a very tricky question," Finney said, "because if you have ever sat and watched by a campfire, then what puzzles you is that the flames are always floating around. How do you characterize this non-steady state phenomenon to counteract it? Modeling?" Finney learned that light ground fuels ignite strictly by convection, and they usually consume themselves in 30 seconds or less at about 1,500 degrees. Heavy fuels like wood and fallen trees will smoulder or burn in the embers for hours or days and release heat throughout the process. They tend to burn and quickly release their stored energy in continuous wind. It's like blowing a bonfire.

While conducting basic research, Finney stumbled upon a book

, About the Allied bombing campaign during World War II. He learned that the commanders of the United Kingdom and the United States, while waging wars against the Germans and Japanese, found that it was easier to burn cities than to blow them up. The trick is to knock the building down first and then set it on fire. It was in 1945 that the Royal Air Force carried out on Dresden, Germany. Military intelligence personnel studied reconnaissance photos to discover older areas built mainly of wood, and then used high explosives to conduct saturation bomb attacks on them. The second wave of planes attacked these areas with more than 2 million pounds of incendiary magnesia bombs. This has the ideal effect of igniting urban fires, but it also caused some unexpected situations. Soon after all these buildings were burned down (which happened for 30 minutes), a huge hot smoke emanated from the sky over Dresden, which appeared to resemble a thunderstorm.

The Dresden fire produced a powerful hurricane wind, which was enough to uproot and chop giant trees in half, attract the gables and furniture of the roof, and make countless people fly into the rotating tornado like fallen leaves. Before that, the fire completely destroyed several square miles of the city.

Finney also unearthed a bunch of obscure research reports published during the Cold War that analyzed the Dresden fire and similar thunderstorms over Hiroshima after the atomic bomb exploded (still about 30 minutes later). One of these reports was commissioned by the Defense Nuclear Agency (Defense Nuclear Agency) and compared storms caused by bombing with those caused by natural disasters. For example, during the Tokyo earthquake in 1923, a strong cyclone The pontoon was lifted from the river, and the river itself nearly 50 feet into the air-almost all personnel were killed before hitting a military warehouse where 40,000 people had taken refuge.

Another of these reports, titled

Published by the Forest Service in 1964, it studied what would happen if the national forest was hit by a nuclear weapon. The author calculated that the explosion of a multi-million-ton warhead could ignite up to 1,200 square miles at the same time and cause a fire that eventually burned 10,000 square miles. Those involved in the research are clearly aware that naturally occurring wildfires will cause at least the same level of damage in theory. This is especially frightening given the surge in the population of the flammable wasteland in the west. To better understand this risk, the Forest Service conducted a series of huge field tests in which they laid out a grid of streets similar to cities and suburbs on federal land in Northern California. Every home site in these communities was filled with wasteland fuel (in some cases juniper and pine) and started to burn. Not only did this produce small tornadoes; it also confirmed that wild fuel fires burn very similarly to the fires of World War II.

Finney told me that when he read all these things, some voices rang. "I realized,'Oh my God, we are creating conditions for the fire,'" he said. "These fires are not only caused by climate change or certain accidents. They are big because our cities are like cities, full of heavy fuel that burns for a long time."

In August, a fire broke out in Healdsburg, California, which was part of a fire that burned nearly 400,000 acres of land in the area.

In a fire, whether it was in wartime bombing operations, fireworks like plume smoke, or the wind fire that destroys heaven, it seems that many light and heavy fires are burning at the same time. There are light winds around them. , Can provide fuel on a large area. As large areas continued to burn with hot and smoldering embers for several hours, the individual convective pillars of all the many small fires began to converge into a single giant plume. As the hot air in the plume rises, something must replace the air at the bottom of the plume-more air, that is, air drawn in from all directions. This can create a 360-degree wind field that blows directly to the flame. The effect is the same as the forged vent holes. It oxidizes the fire and pushes the temperature high enough to even convert heavy fuels (giant construction timbers, mature trees) into mature fuels. Burning burning. These heavy fuels then pump more heat into the convection tower, creating a feedback loop: the tower rises faster and absorbs more wind, as if the fire has found its way.

The project not only produced small tornadoes; it confirmed that wild fuel fires burned very similarly to the fires of World War II.

This seems to be what happened during the Carl fire. Neil Lareau, an atmospheric physicist at the University of Nevada, said that a weather balloon released on the morning of July 26 found a layer of warm air thousands of feet above the Sacramento Valley, the so-called reverse Thermosphere.

When Knapp settled in his office, this reversal layer trapped Car Fire's hot plumes of smoke near the ground. But over time, the plume of high temperature pushes it to higher altitudes and keeps cooling down.

Around the time Knapp was jogging over the river to look at the fire, the plume reached 18,000 feet, high enough to hold water vapor, floated high in the sky, condensed into liquid cloud droplets, and produced a pyrocumulonimbus or fire source. Revolving thundercloud. The process of condensing hot vapor or steam into liquid releases heat. You can think of it as the inverse process of the cooling effect caused by evaporation, just as all of us have felt it coming out of the swimming pool to the wind. In the case of a fire plume, the condensation of water vapor into a liquid cloud drop will transfer new heat to the plume itself, causing it to rise faster and higher.

At the same time, returning to the ground, the rising plume attracts new air by sucking in two pre-existing wind fields, which Knapp noticed were blowing from the south and northwest winds. The two winds incline and incline each other, and intersect at the front of the flame, and then entangle and wrap around each other in the flame, forming a rotating vortex. The higher the plume rises, the faster the vortex spins. Lareau compares it to a figure skater: “The skater starts to spin slowly, stretches out his arms, then pulls his arms inward, perhaps lifting it above his head, and then suddenly starts spinning very, very fast.”

As the tornado shattered the house and sent burning debris to the sky above Knapp, this created one of the most dangerous plume phenomena-the fire-breathing trademark rain. Classic ground-driven wildfires will only ignite the direct area that intersects with the fire's own shallow flame front. In contrast, falling sparks caused a plume of fire to burn and spread from the core for miles, as if firing a fire bomb to ignite a new large-scale fire, like an explosion near Knapp.

"If you draw a map of California, I can provide you with 150 communities, the comprehensive factors of these communities are exactly the same as heaven."

Brian Estes, Head of CalFire

Such fires are almost impossible to extinguish, because they may move too fast for firefighters to avoid injury, burn too hot to be extinguished, and because so many people in the West settle in these fires more and more Occurring in many places-the urban interface of the wilderness, or WUI (pronounced woo-ee), spreads across many mountains in California.

"We have crammed thousands of people, roads, houses and yards into this highly turbulent Mediterranean climate," said CalFire chief Estes, who grew up in the town of Paradise. To make matters worse, Estes said, many of these people tend to be quaint gold rush towns, like paradise, which happens to sit on top of the drainage system of rivers and creeks, where wildfire fuel accumulates and the wind is blowing. Especially violent.

Estes said: "If you draw a map of California, I can provide you with 150 communities, the combined factors of these communities are exactly the same as heaven."

According to Estes, in all these communities, “when we suffer a catastrophic fire, we have to drive those people out, which makes things more complicated and I can’t even tell you.” Estes added Said that for at least the first 16 hours of the bonfire in his hometown, firefighters mostly just drove residents out of their homes and used bulldozers to clear the road blocked by the driver and escaped by the car abandoned by the pedestrian. Estes said that during the entire period, “none of the fire trucks could put out the fire. They were all trying to rescue people.”

Knapp took this photo of "The Redding Carr Fire" because it began to twist into one of the strongest tornadoes ever recorded.

The climate change in the room is of course the cause of climate change, and it has even pushed our current nightmare to the possibility of a massacre beyond imagination. Knapp, Finney, Collins and several other researchers (most of whom are now involved in the research of Pyregence, the Federation of Fire Sciences) have identified a particularly terrifying way that could happen . Current climate change patterns indicate that winter snow will be less and less in the West, summer hotter, drought more and more severe, extreme fire weather is becoming more and more acute-long-term dry heat will dry the moisture in the turf and trees, Coupled with the violent wind, even a small spark whipped into a big fire. At the same time, the collapse of commercial logging is mainly due to environmental regulations, coupled with our collective intolerance of prescribed burns (no one likes smoked air), which has caused forests to grow into unnatural dense young trees. More trees means more roots competing for the same groundwater. During the California drought from 2011 to 2016, this game, with the help of bark beetles, killed an astonishing 150 million trees, the largest mass death in the history of the United States.

No one knows how all these dead trees will affect wildfires. Preliminary studies have shown that dead trees will moderately increase the risk of serious fires within a few years, because dry needles help the fire spread from canopy to canopy, rather than along the forest farm. Once all these pine needles have fallen (which seems to be happening now), the risk of a fire is expected to decrease within a period of time. People think the most terrifying part is that at least 10 or 15 years later, it is expected that all 150 million dead trees (estimated 95 million dry tons of firewood) will fall on the already deep pile of fine conifers. Duff is full Small branches and growing branches. At that time, we will work together to prepare the entire western slope of the Sierra Nevada Mountains through taxpayers' money for more than a century. The money is ostensibly designed to protect the economic value of the wilderness and wood to burn the largest fire in human history.

The California state government has neither lost this terrifying long-term risk nor the general trend of destructive fires. This is how Pyregence was born. Coordinated by Saah of the University of San Francisco, Pyregence has set out to create a new software ecosystem that includes large-scale fires and plume-driven large-scale fires. The idea is to help firefighters respond on the one hand, and to help the rest of us make informed decisions about urban planning and fuel disposal such as prescribed burns. For any laboratory, the overall challenge is too big and urgent, so Pyregence has divided it into a distributed Manhattan project of collaborative fire model research.

Finney joined a Pyregence working group to study the behavior of large wood fuels accumulated deep, such as in the national forests of our west. Field researchers went out to make detailed measurements of the wildfire fuel bed, and Finney, who returned to Montana, commissioned the construction of a new combustion chamber the size of a grain bin. Once completed, the room will allow him to replicate the wildfire fuel bed by stacking logs and other materials up to a few feet deep. Then, he will ignite them, hit them with wind and moisture, and quantify their burning rate and energy release rate, which is what he calls the "thermal part of the fire."

Finney said: "What we really want is how these things turn into burning things. They are not just smoldering on the forest floor, but how can they actively participate in these fires?"

If all goes well, Finney’s working group will finally perform 3D digital simulation coding on various field fuel beds. In essence, the digital cube is no different.

Voxels-can be stacked and arranged in an infinitely variable manner in the entire landscape generated by GIS mapping data.

Another team led by Janice Coen of the National Center for Atmospheric Research divided California into eight fire zones and studied the severe past fires in each area. By analyzing the propagation mode and time of these flames, Coen's team determined the days when the fire increased at an alarming rate, and then combined weather station and satellite data to obtain two sets of relevant data: local weather conditions (such as hot local wind and continuous Extreme fire-related) growth; and large-scale weather patterns of 500 miles or more that continue to be associated with these local conditions. Hope to create a weather warning system for extreme fires in each region. Coen has conducted a proof-of-concept test using an experimental model called "Atmospheric Coupled Wilderness Fire Environment" or CAWFE

). CAWFE is an atmospheric weather simulator, combined with a fire propagation algorithm, so that Coen can insert precise local and large-scale weather events such as Carr Fire that occurred in the past. She even triggered the ignition at the exact moment Carl's fire started and watched the fire tornado spin on its own. According to Saah, who is also the managing director of the Spatial Informatics Group, an environmental think tank, the hope is that one day a fuel model will be used to supplement the fire spreading part of CAWFE, just like Finney hopes to produce, accounting for huge additional costs. . Heat produced by heavy fuel burned for a long time under an open flame. Then, by providing real-time real-time weather data, Pyregence should one day be able to produce accurate near-term predictions of fires caused by extreme plumes across California for the first time.

At the same time, at UC Merced, a climate researcher named LeRoy Westerling leads a Pyregence team responsible for solving the vital long-term problem of how to prevent the apocalyptic fires in the future. Westling said this becomes especially urgent when you consider that each future fire season in the western United States may be worse on average than the previous one. "How do you adapt? It's not just California," he said. "The entire West Coast, the Rocky Mountains, and parts of Canada and Alaska take off regularly. Therefore, the scale of managing fires within that geographic area at the same time is shocking, even to the psychological impact of coexisting with it." As a solution, Westerling's team is even now developing what Saah calls the "statistical machine learning monster"-a large simulation engine that allows researchers to operate in a variety of remote climate conditions, where ground fuel, conventional firepower and even land management are like prescribed burns. The practices will affect each other. In an ideal world, this would lead decision makers to ask the following questions: If we are caught in apocalyptic climate change, but carry out many sensible regulations to burn, and only allow fireproof construction in mountainous areas, then 50 years from now What will happen to the blizzard? What does it look like now?

In August, a thunderstorm near Napa, California triggered the aftermath of a fire.

The wildfire season began in mid-August, the hottest on record, when a dry thunderstorm caused 12,000 lightning strikes in a week and ignited hundreds of fires. By the beginning of September, three aircraft had become the largest in the history of the state, and strong northeasterly winds blew them to a brand new superlative state. Near Blodgett Forest, these northeasterly winds pushed relatively small raging fires into huge scorched rain forest storms. In 24 hours, it spread over 230,000 acres, one of the largest single-day fire spreads in history, destroying hundreds of buildings and killing 15 people. Throughout the Sacramento Valley, the same wind merged other wildfires into the huge August Complex, the largest fire in the state's history, nearly one-eighth, covering more than 850,000 acres.

Even more surprising was the small river fire that ignited on September 4 in a dead tree-lined area in the southern Sierra Nevada Mountains. By the next day, a huge hydrothermal rain dragon formed and helped burn 115,000 acres of land, traversed so many lakes, cabins, and campsites, somehow tore huge living trees from the ground and Throwing to the road, more than 360 people and 16 dogs were trapped on the shore of the Mammoth Reservoir. In turn, this forced the California National Guard to use military helicopters to rescue hundreds of people overnight, something that has never been done before.

"That's a weird beast," said Saah of the Creek Fire. "In our research team, there was a lot of dialogue around that particular fire because it was behaving beyond normal levels." The most peculiar fact is that the energy release in the center of the entire small river fire is still related to the high temperature and the surrounding surroundings. The same as high temperature. This classic sign of a large-scale fire is likely to mean that the terrible part—the future of 150 million dead trees burning in flames—has arrived. Saa said: “If you look at the satellite image of the Creek fire, it’s like a nuclear bomb exploded. It’s crazy, it’s just its behavior, intensity and growth rate.”

Atmospheric physicist Lareau is also stupid. He said: "I'm a bit at a loss." "I've seen a lot of fires, and huge scorched cumulonimbus clouds have been produced in Sierra. I mean, this thing blows everything out of the water." Instead of expanding the clouds to 40,000 feet, it is better to extend it to 50,000 feet. It will produce a long-lived tornado strain vortex within a few hours. "

These whirlpools rounded huge living trees and smashed them on the ground, some in the camp, some on the road, blocking the escape route. The plume of the flame will also produce lightning, which lasts for 12 hours. Another anomaly is called plume collapse. In this behavior, all the hot rising air suddenly reverses its direction after it becomes higher, and it is strong toward the middle of the flame. Indecent, thus forcing the fire to spread. It spread out in all directions, igniting huge new land.

"In my opinion, this may be one of the strongest storms we have ever seen," Lalo said. "I think in many ways, this is more intense than the Karl Farr fire."

Of course, there is no more fire than Karl. Especially at that moment, when he found himself in a cloud of hot tree bark, and a match was burning at the same time, he ignited the surrounding houses. At that time, Knapp recently told me: "I just need to realize that I don't have all the safety equipment, I don't have any fire fighting resources"-no one needs help-"I have a family on the other side of town."

Knapp drove to his car and drove into the traffic jam of the terrible neighbor. Slowly, the tornado roared overhead, surrounded by their own houses, and they drifted away along the path to safety. The next day, Knapp drove back to see Dirkson's house. More than 60 houses near her were destroyed overnight, including the one next door. A single ember slowly burned through the ground screen vent at Derksen's location, igniting the floor. It seems that the firefighters in the past had put out the fire before it got out of control.

As Knapp said, the scene was "full of sorrow," not only because he and everyone else (the forest without trees) did not realize the degree of danger they were in.

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