Understanding Fire Hero Image

Understanding Fire

Wildfires in California aren’t what they used to be.

there's a new urgency to find better ways to fight and prevent fires.

discover how CSU faculty and students are doing just that.

Is California on fire? We already know that wildfires in the West are worsening every year. They are bigger, hotter and more deadly and destructive. Fires now start sooner and last well beyond the traditional “season,” which once ran from June to October. An extended, if not a year-round, fire season is now the new normal.

In this first article in a new series on California's wildfires, we ask CSU faculty experts and researchers to explain how fires are different now; what we’re learning about fire behavior; and better ways California can manage fires in the future.

NASA astronaut Ricky Arnold captured this image of California wildfires on August 3, 2018 from his vantage point on the International Space Station. Photo courtesy of NASA



The forest floor grows dense with flammable dead branches and brush when it’s not cleared out, either manually or when burned. In many parts of California’s wildlands, these forest "fuels" have not burned or been cleared for decades, due in part to fire suppression policies by state and federal agencies.

"One of the reasons we're observing more fires is because of 100 years of poor Forest Service policy where we didn't allow prescribed fire or wildfires to burn," says Craig Clements, Ph.D., director of the San José State University's Fire Weather Research Laboratory and associate professor of meteorology and climate science.

To understand the history and context of wildfire suppression in the U.S., you have to go back to the Great Fires of 1910. After these enormous wildfires ravaged three million acres across Idaho, Montana and Washington, the then-young U.S. Forest Service made it their singular policy to stop fires whenever possible.

It wasn’t until the 1970s that policy shifted from fire control to fire management, with the recognition that some fire—including prescribed burns—is a necessary part of the wildland ecosystem. But decades of still-unburned forest means today’s wildlands are dense with vegetation that’s ready to spark. Drought conditions have only intensified the impending threat in many parts of the state. (See below for more on this.)

In a 2009 report, Chris Dicus, Ph.D., professor of wildland fire and fuels management at California Polytechnic State University, San Luis Obispo, wrote that before the Gold Rush, there were approximately 50 to 70 trees per acre in California’s forestlands. Today, there are more than 400 trees per acre.

Another contributing factor to the growing forest fuel load is the increasing number of dead or dying trees caused by bark beetle infestations. These insects, along with the drought, are responsible for killing 129 million trees across California since 2010, quite literally adding fuel to the fire.


Studies show that climate change contributes to our droughts, Dr. Clements says. Less water means drier, more combustible vegetation. Add to that record-breaking heat waves, and you’ve got even drier fuels.

Warmer climates may also increase bark beetle activity and population growth, which creates more dead trees that are ready to burn.

California’s Fourth Climate Change Assessment found that, if greenhouse gas emissions continue to rise, the frequency of extreme wildfires will increase, and the average area burned statewide would grow by 77 percent by 2100.


Where there are people, there is fire. Ninety-five percent of wildfires in California are caused by humans, whether by accident or deliberately.

What makes matters perhaps worse in California than many other Western states is the ever-growing number of people and homes encroaching on the wildland-urban interface (WUI), a technical name for the transition between wildlands and established municipal areas. Homes in these fire-prone areas are more vulnerable to fire, and fire agencies have to spend more to protect them.

Between 1990 and 2000, 60 percent of all new​ housing units built in the U.S. were located in the WUI, with major development along the West Coast.

Jacquelyn Chase, Ph.D., a professor in geography and planning at California State University, Chico and a Butte County planning commissioner, believes we shouldn't build new homes in these areas.

“It seems like we're really out-of-step with what we know about the risk of fire now compared to flooding, for example,” Dr. Chase says. “Some people are saying we should just treat fire like we treat floods. You wouldn't build on a floodplain. But people build all the time in high-risk [fire] areas.”

She points to several subdivision communities in California’s WUI that were destroyed by wildfires in the last decade: Keswick Estates (Redding), The Trails (San Diego County) and Coffey Park (Santa Rosa). Fires likely spread to these communities through burning embers carried by the wind—a phenomenon known as spotting. ​Santa Rosa residents affected by the Tubbs Fire, which destroyed 5,000 homes, “were deep inside a suburb, but they were burned by embers coming from the hills not too far away,” Chase explains, adding that she hopes future city planners and developers will stop building in the WUI.

Homes situated in or near wildlands are at greater risk for burning. While fire-safe landscaping and removing brush helps, it may not be enough to protect houses from fires spread by embers.

Wade Martin, Ph.D., professor of economics at California State University, Long Beach and co-author of the book, “Wildfire Risk: Human Perceptions and Natural Implications,” asks, “When people are moving into these areas, do they have information on the risk they’re buying into?”

“Generally, we find that people [overestimate] being in nature as a positive and undervalue the risk from wildfire. The risk of having your home destroyed is really pretty small, but it is catastrophic when it happens,” says Dr. Martin, who is currently conducting research in Australia on homes in at-risk fire areas to better understand how homeowners weigh the benefits and risks of living close to nature.

Homeowners who already reside in the WUI should do everything they can to make their home more resilient to the threat of wildfire, Chase says. One of the most important steps is to remove all the vegetation or dried fuels at least 30 feet around the house—what’s called creating a defensible space. But Chase cautions that sometimes even “firewise” landscaping like this isn't enough, as shown by the destruction of buildings in Santa Rosa and Redding.



When humans learned to control fire, we changed the course of evolution forever. But that definitely doesn’t mean we understand everything about this unbelievably powerful natural phenomenon. Here are three things we're getting smarter about:


Weather is the least predictable part of fire management, so understanding weather conditions can go a long way in helping firefighters determine exactly how a fire will spread.


Fire Behavior Triangle: Firefighters learn about the 3 major factors that affect a fire's behavior-weather, fuel & topography

The Fire Behavior Triangle: Firefighters learn about the three major factors that affect a fire's behavior—weather, fuel and topography—in this diagram. Weather conditions, such as low relative humidity, warm temperatures and high winds, make a perfect environment for fire to thrive. The topography, or the slope and natural features of the earth's surface, can influence the direction and speed of a fire. For example, fire tends to travel uphill faster than downhill.

It’s not just external weather conditions that affect a fire’s behavior. Fires actually create their own weather patterns, too. One example is a fire whirl, or fire “tornado,” like the one seen at the Carr Fire in Redding during the summer of 2018. San José State's Dr. Craig Clements explains that, while fire whirls are not rare, the sheer size of the Carr tornado—1,000 feet wide—was unusual. And devastating.

So how do fires create their own weather? To explain, Clements compares wildfires to a typical campfire: A thermal column of hot gasses rises from the top of the fire. At the fire's base, air rushes in, providing oxygen so the fire can continue to burn. As the fire continues to suck in air, it modifies the wind and thereby creates its own weather pattern.

Dr. Chris Dicus, a wildland fuels and fire management professor at Cal Poly San Luis Obispo, demonstrates unique fire behavior in his fire ecology lab.

In his fire ecology course, Dr. Dicus teaches students about fuels and other variables that can affect a fire's behavior.

It’s these fire-created winds that leading researchers like Clements are currently working to learn more about. “We don't know exactly how far they extend out, or how they affect the fire behavior in terms of pushing the fire in different directions," he says.

“Fires can also produce their own clouds—we call those pyrocumulus clouds,” and they’re not just smoke plumes but actual clouds made up of water droplets. “And if they’re really deep, they’re called pyrocumulonimbus, because they’re almost like a thunderstorm,” Clements explains. Some fires even create their own thunderstorms and lightning.

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Watch a fire "tornado" demonstration at Dr. Chris Dicus's fire ecology lab at Cal Poly San Luis Obispo.


Simply put, Craig Clements at San José State has transformed wildfire research. His meteorological techniques to study fire behavior, such as using special instruments to measure wind turbulence during a fire, have been pioneering.

“Nobody had done this before,” Clements says, adding that data from his initial doctoral research at the University of Houston are now used as the international standard for fire simulation models using atmospheric data.

At SJSU, Clements’s Fire Weather Research Lab also broke new ground in its use of mobile atmospheric measuring systems to study wildfire winds. One of the lab’s trucks is equipped with a Doppler LiDAR (Light Detection and Ranging), which uses a pulsed laser to measure distances and collect smoke data from within fire plumes. A second truck will soon have a mobile Doppler radar unit, allowing the scientists to collect data on clouds created by fire.

The SJSU Fire Weather Research Lab's mobile team has trucks equipped with radar and LiDAR technology to collect data about how weather and fire interact.

With more sophisticated wildfire-weather data, scientists will get better at predicting what a fire will do, in turn allowing firefighters to manage wildfires faster and more safely.

Clements's research team currently includes six graduate and four undergraduate students, all of whom get hands-on field experience measuring wildland fuel and weather data. Three students also serve on the mobile fire deployment team that goes to active wildfires to collect data on fire spread, smoke plumes and other weather-related fire behaviors.

“We are the only team that has made these kind of observations of active wildfires,” he notes. In fact, they are the only meteorological team in the U.S. trained as firefighters and listed as a national resource so they can be requested to any fire incident. “And that’s not easy to do,” says Clements, explaining that he and his students can be requested by a fire agency’s incident management team and assigned to a fire. (His mobile deployment team members become trained firefighters and are issued an incident qualification card—aka "red card"—so they are permitted access to fire locations.)

With the combination of LiDAR and radar tools, Clements and his team hope to be able to detect the rotation of a fire column in real time at a distance and to detect downdrafts that could change the direction of the fire spread. He also hopes the new radar tool will help shed some light on the process of spotting, or how volatile embers travel and start new fires, a perplexing problem. Currently, he says, “we have no idea how to forecast ember transport and spot fires.”

“you CAN see hurricanes coming for days. you can measure storms. we can forecast severe weather, but we're not really doing that on wildfires yet."

—Dr. Craig Clements, San José State UNIVERSITY Fire Weather Research Laboratory


At California State University Channel Islands, Sean Anderson, Ph.D., and his team of mostly undergraduates at the PIRatE Lab (short for the Pacific Institute for Restoration Ecology) use drones to monitor and manage land affected by wildfire and other disasters.

Dr. Anderson, who is chair and professor at the Environmental Science and Resources Management (ESRM) program, loves giving students hands-on experience in collecting environmental data, such as aerial drone maps of burn areas after a wildfire, pollutants in the ocean after an oil spill, or measuring ecosystem impacts after a hurricane

By moving in immediately after a disaster, Anderson and his students learn about the large-scale impact of these events on the environment.

“When disasters strike, we strike right back," says Anderson. "Our students are capable field professionals who know how to work with fire, police, incident command, and bring with them the technological tools to collect time-critical environmental data."

And thanks to the flexibility and applied-research focus of the CSU and the Channel Islands campus, his team can deploy quickly to collect data before it disappears. So, when the Thomas Fire broke out in Santa Barbara and Ventura counties in December 2017, they were ideally positioned to respond with drones that mapped burn areas, for example.

Anderson and his ESRM students then shared that information immediately with the community. During and after a fire, the first thing evacuated residents want to know, of course, is whether their home is okay. Local agencies often aren’t able to answer those questions quickly, says Anderson, because they’re busy fighting the fire. During the Thomas Fire, his students responded by creating a popup website to provide real-time information about where the fire had and had not traveled.

After the 2017 Thomas Fire, Dr. Anderson's CSUCI students used drones and GIS mapping to observe and report on burned and unaffected areas. In the process, they made an architectural discovery.

Anderson’s students also used drones and GIS (geographical information systems) to create a detailed 3D map of the burned Ventura Botanical Gardens. The map revealed previously undiscovered 100-year-old rock walls that had been covered with vegetation prior to the Thomas Fire. His next drone project will be a mapping initiative to reveal naturally occurring oil seeps that are still burning underground with the help of new thermal imaging-equipped drones that can detect harmful fumes.

Further south, students at California State University San Marcos recently partnered with a local drone manufacturer and local fire agencies to research how the machines could help first responders to deliver supplies such as hoses and other firefighting gear.

​The Holy Fire shot from Lake Elsinore in August 2018.


There's still much to be learned about fire-induced weather and how to better predict wildfire behavior.

With ongoing research, Dr. Clements sees a future where we’ll be able to forecast a fire’s direction and spread, like meteorologists already do with severe weather patterns.

“You see hurricanes coming for days ... measuring storms with the radar network around the U.S. So we can forecast or 'now-cast' severe weather, but we’re not really doing that on wildfires,” Clements notes.

Imagine a near-future in which a wildland firefighter gets the call to head to a fire. Before she's even suited up, the detection tools on her truck are automatically collecting smoke plume and cloud data from hundreds of miles away and sending it to a satellite that feeds information to a mobile app for fire management and forecasting. The firefighter can then predict the fire spread via her mobile phone.

Next-generation firefighting tools like these aren't so far off, thanks in part to Clements and his modeling data research, and other researchers at the CSU and beyond.

“I want to see this technology placed on all the fire suppression vehicles," says Clements. "So when the vehicles are out in the field, they’re collecting wind profiles and firefighters don’t have to worry about it because it’s all automated. It’s just a little laser beam coming out of the truck.

“Hopefully those models can be put into the hands of fire managers," he continues. "Then you can really get a handle on what a fire is doing, where it’s going and you can forecast it better.”

This article is the first in a series on the California State University's role in understanding, preventing and fighting California's devastating wildfires. Our continuing coverage features a dedicated wildland firefighting crew made up of mostly CSU students and alumni who are working hard to stop wildfires throughout the state.

Story: Hazel Kelly

photoGRAPHY: PATRICK RECORD, nasa, San José State University, CSU Channel Islands

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