Planning evacuations using dynamic fire vulnerability mapping

satellite photo Camp Fire Paradise California
Camp Fire as seen from NASA Operational Land Imager on Landsat 8 at 10:45 PST November 8, 2018. The photo, enhanced with infrared imagery, was taken about 4 hours and 15 minutes after the fire started.

In the last three years examples of wildfires in North America that have caused massive evacuations, fatalities, and structures destroyed include:

City officials in Paradise had an evacuation plan in place and had even conducted a drill, but the plan assumed a specific fire situation that would allow time for sections of the city to evacuate, one area at at time. The Camp Fire, driven by strong winds, hit the community so quickly that the entire city had to evacuate immediately, causing the limited and low volume evacuation routes to become clogged. A situation like that with very little advance notice would overwhelm many cities, especially if the availability and capacity of routes can’t come close to handling the traffic.

Managers can use computer models to predict the spread of fires, and there are also models that can estimate how much time it would take to evacuate people in vehicles or on foot. But these models have not been integrated to determine how changes in fire behavior would affect evacuation capability and plans.

A linked fire behavior and evacuation model could have variable inputs for weather, fuels, and topography as well as an assortment of evacuation alternatives that could inform planners about existing and proposed designs.

An integrated modeling system or simulator for dynamic fire vulnerability mapping does not exist, but researchers have laid out specifications and a framework for building one. Their recommendations are detailed in a paper published in Safety Science titled, “An open physics framework for modelling wildland-urban interface fire evacuations.”

dynamic fire vulnerability mapping
Illustration from the researchers. Click to enlarge.

Below is the abstract from their paper:

“Fire evacuations at wildland-urban interfaces (WUI) pose a serious challenge to the emergency services, and are a global issue affecting thousands of communities around the world. This paper presents a multi-physics framework for the simulation of evacuation in WUI wildfire incidents, including three main modelling layers: wildfire, pedestrians, and traffic. Currently, these layers have been mostly modelled in isolation and there is no comprehensive model which accounts for their integration. The key features needed for system integration are identified, namely: consistent level of refinement of each layer (i.e. spatial and temporal scales) and their application (e.g. evacuation planning or emergency response), and complete data exchange. Timelines of WUI fire events are analysed using an approach similar to building fire engineering (available vs. required safe egress times for WUI fires, i.e. WASET/WRSET). The proposed framework allows for a paradigm shift from current wildfire risk assessment and mapping tools towards dynamic fire vulnerability mapping. This is the assessment of spatial and temporal vulnerabilities based on the wildfire threat evolution along with variables related to the infrastructure, population and network characteristics. This framework allows for the integration of the three main modelling layers affecting WUI fire evacuation and aims at improving the safety of WUI communities by minimising the consequences of wildfire evacuations.”

Authors of the paper: Enrico Ronchi, Steven M.V. Gwynne, Guillermo Rein, Paolo Intini, and Rahul Wadhwani.

Researchers find prescribed fire smoke to be less harmful than that from wildfires

Therefore, prescribed fires to protect communities can protect residents in more ways than one

Wolf Trap National park prescribed fire
Prescribed fire at Wolf Trap National Park, April, 2018. NPS photo by Nathan King.

Researchers studying the effects of smoke on children found prescribed fire smoke to be less harmful than smoke from wildfires. The Stanford University study looked at three groups of children:

  • Those who were exposed to smoke from a prescribed fire;
  • Children exposed to smoke from a wildfire in which no structures burned; and,
  • Children that were not exposed to smoke.

Sometimes fire personnel refer to a prescribed fire as “good fire”. Now they may call smoke from a planned burn as “good smoke”. A way to look at this research is that removing hazardous fuels near a community is a way to reduce the threat of a wildfire spreading into the town and burning structures or entrapping and killing people. And, removing the fuels with good fire rather than allowing a wildfire to burn the same area, exposes residents to less harmful smoke. For fire-prone areas, it is not IF it burns, it’s WHEN. Do you want your smoke now under controlled conditions or later, possibly under extreme conditions?

From Stanford University:


…The study was published May 30 in the European Journal of Allergy and Clinical Immunology. It was conducted in Fresno, California, a city with high air pollution levels due to its topography and other sources, including traffic and agriculture.

“This study suggests that exposure to wildfire smoke is detrimental above and beyond poor air quality,” said the lead author, Mary Prunicki, MD, PhD, an instructor of medicine.

The study’s senior author is Kari Nadeau, MD, PhD, professor of medicine and of pediatrics and director of the Sean N. Parker Center for Allergy & Asthma Research at Stanford.

Native Americans traditionally used controlled burns to manage California’s forests, but throughout the early 20thcentury, wildfires were widely suppressed. This began to change in the 1960s and 1970s, when scientists recognized fire as a normal part of forest ecology. Recent wildfires have brought more attention to the possible benefits of prescribed burns as a way to reduce fuel levels and wildfire risk, but not everyone is enthusiastic.

Opposition to controlled burns
“We know that there’s some public opposition to doing prescribed burning,” Prunicki said. “It’s our feeling that prescribed burning, because it’s so controlled, may expose people to fewer health effects than wildfires.” Prescribed burns are of lower intensity and are permitted only when weather conditions allow the fire to be contained.

In the study, the researchers compared blood samples from three groups of children, all of whom were 7 or 8 years old. One group of 32 children had been exposed to smoke from a 553-acre prescribed burn that occurred in March 2015; a second group of 36 children had been exposed to smoke from a 415-acre wildfire in September 2015. Both fires were about 70 miles away from Fresno, and blood samples were collected from the children within three months of each fire.

The study also included blood samples from a control group of 18 children who lived in the San Francisco Bay Area and had not been exposed to wildfire or prescribed-burn smoke.

The researchers measured air pollution levels recorded at four monitoring stations in Fresno and estimated pollution levels at the children’s homes during the fires based on how far they lived from the stations.

Pollutant exposures were higher in the wildfire group compared to the prescribed-burn group.  The air pollutants measured included nitrogen dioxide, polycyclic aromatic hydrocarbons, elemental carbon, carbon monoxide and particulate matter.

Wildfire smoke exposure was associated with lower blood levels of type-1 T helper cells, a group of immune cells that are involved in the immune response. Among children exposed to wildfire smoke, the researchers also saw increased methylation of the Foxp3 gene, indicating reduced activity of this gene, which is broadly involved in modulating allergic and other immune responses. The finding of greater Foxp3 methylation is congruent with earlier studies of the effects of air pollution on the immune system, Prunicki noted.

Significance of particulate matter
One important aspect of the study was that the September 2015 wildfire was confined to forested areas and did not burn any structures.

“Particulate matter from wildfires is different from region to region and depends on what is burning,” Prunicki said. “When a wildfire is going through a town, there are a lot of concerns about what happens to the chemicals in people’s homes and cars when they go up in flames.” Smoke from wildfires that burn inhabited areas almost certainly has worse health effects than those found in the current study, she said.

The researchers plan to conduct larger, more detailed studies of the effects of wildfire smoke on health. They will be enrolling healthy people in a trial at Stanford later this summer to collect baseline data from blood samples. When future wildfires affect Bay Area air quality, the participants will be asked to provide follow-up blood samples.

The scientists also plan to research the health effects of using home air purifiers during wildfires, as well as measure the protection offered by N95 masks, with the aim of developing recommendations for when masks should be used by different populations, such as healthy adults, elderly people, children and people with chronic illnesses.

The study’s other Stanford co-authors are biostatistician Justin Lee; life science researcher Xiaoying Zhou, PhD; Francois Haddad, MD, clinical associate professor of medicine; and Joseph Wu, MD, PhD, professor of medicine and of radiology.

New 3D fuel modeling helps predict fire behavior

Combining aerial and terrestrial LIDAR data with new 3D field sampling

By Diane Banegas, Research and Development, U.S. Forest Service

Land managers have a new tool in their firefighting arsenals that models forest fuels in three dimensions. These 3D fuel models have the potential to make firefighting and the management of controlled burns safer and less costly while helping to protect valuable natural resources.

The 3D fuels modeling technique will benefit land managers by allowing firefighters to develop better strategies and helping predict future fire behavior. It was recently tested at Eglin Air Force Base in Florida.

3-d fuels vegetation wildfire
New 3D fuel modeling techniques help land managers predict future fire behavior. Here, Louise Loudermilk (right) and Christie Hawley (left) collect 3D fuels in the field. Photo courtesy: Susan Prichard, University of Washington.

Managers will be able to input 3D fuels from this research into next-generation fire behavior models. This will allow them to test different ignition patterns for a prescribed burn to see how the resulting fire behaves in 3D.

Running 3D simulations can help firefighting teams develop strategies to manage or extinguish future fires as safely and economically as possible.

“These fire models can output various scenarios of fire behavior that help inform quick management decision making,” said Louise Loudermilk, a research ecologist at the USDA Forest Service’s Southern Research Station. The model can also give “burn bosses” choices on selecting the safest approach to meet management and ecological controlled burning objectives while better predicting smoke conditions.

“This work represents a new era in fuels research because it links fuel ecology with fire behavior. In fire behavior models, fuels traditionally are overgeneralized and have been unable to represent how fuels predict fire behavior. Now fuels can be represented dynamically in three dimensions,” Loudermilk said. “This advancement, which has taken over 10 years to achieve, is like going from a board game to a realistic video game.”

3-d fuels vegetation wildfire
Louise Loudermilk ignited a prescribed fire with a drip torch for management and ecological objectives. A new 3D fuel model can help make the management of controlled burns safer and less costly. USDA Forest Service photo by Christie Hawley.

The modeling technique combines aerial and terrestrial LIDAR data with new 3D field sampling, historical data about when an area last burned and simulation modeling to provide 3D fuel characterization at multiple scales. Data collected from a landscape of interest includes vegetation type, fuel mass and fuel volume, all represented in 3D.

Loudermilk co-authored a research paper about a new method of field sampling used for this modeling technique. “The method works equally well across small or large landscapes,” she said. “Our goal is to provide big data collections that will one day be downloadable for anyone to use.” She also contributed to a book chapter about the 3D modeling technique and the importance of fuels research. A related paper in Forest Ecology and Management explains how the status and trends of plant diversity can be monitored at a landscape-scale, information valuable for 3D fuels monitoring.

Ultimately, extensive 3D data collected on fuels will be available for landscapes across the United States. Any land manager will be able to select the data for their area and run 3D fire simulations for educational or fire management purposes.

The success of these projects has been dependent on Loudermilk’s extensive network of federal, state and private organization collaborator

3-d model wildfire fuels
Output from processing of terrestrial laser scanning data, representing an important fuel characteristic “surface area” as illustrated by the different colors. This is input to next-generation fire behavior models. Image courtesy Eric Rowell, Tall Timbers Research Station.

Resilience of Yellowstone’s forests tested by unprecedented fire

In 2016 some areas in Yellowstone National Park that burned in the 1988 fires unexpectedly burned again, and with surprising intensity

Maple Fire burns at Yellowstone National Park
The Maple Fire burns at Yellowstone National Park in 2016. The fire affected forests recovering from the park’s historic 1988 fires. PHOTO: NATIONAL PARK SERVICE / JENNIFER JERRETT

By Kelly April Tyrrell, University of Wisconsin

In August 2016, areas of Yellowstone National Park that burned in 1988 burned again. Shortly after, in October 2016, ecologist Monica Turner and her team of graduate students visited the park to begin to assess the landscape.

“We saw these areas where everything was combusted and we hadn’t seen that previously,” says Turner, a professor of integrative biology at the University of Wisconsin–Madison who has closely studied Yellowstone’s response to fire since 1988. “That was surprising.”

In a study published this week [May 20, 2019] in the Proceedings of the National Academy of Sciences, Turner and her team describe what happens when Yellowstone —  adapted to recurring fires every 100 to 300 years — instead burns twice in fewer than 30 years. Yellowstone as we know it faces an uncertain future, the researchers say, and one of the big questions they hope to answer is whether the forests can recover.

yellowstone fires reburn
The pile of rocks with the nail in the middle signifies a long-term study plot Monica Turner and her research group established at Yellowstone National Park in 1990 following the park’s historic 1988 fires. This same plot burned again in 2016. Historically, fires burn in Yellowstone only every 100 to 300 years. PHOTO BY: MONICA TURNER

With Rapid Response Research funding from the National Science Foundation, Turner and her team returned to Yellowstone in the summer of 2017 to study the areas that re-burned. These include the Maple Fire, which burned 28-year-old lodgepole pines that regenerated following the 1988 North Fork Fire, and the Berry Fire, which contained 28-year-old lodgepole pines that had regenerated after the 1988 Huck Fire and 16-year-old trees that regenerated following the 2000 Glade Fire.

In each area, they compared to areas that burned in 1988 or 2000 but did not burn again in 2016.

Continue reading “Resilience of Yellowstone’s forests tested by unprecedented fire”

About a quarter of lightning-caused fires that grow large are not reported within first 7 days

holdover lightning-caused wildfires
(From the research) Locations of lightning-initiated holdover wildfires in the contiguous United States which grew to sizes ≥4 km2 between 2012 and 2015. Map was created using ArcGIS® software by Esri. Basemap is a source of the National Geographic Society and Esri (2019).

Researchers have found that about a quarter of the fires caused by lightning that grow to more than 4 km² (988 acres) are reported more than a week after they are ignited.

A paper published in the Fire Open Access Journal describes how the National Lightning Detection Network (NLDN) and U.S. Forest Service fire data were used to determine the correlation between lightning strikes and the reported location of lightning-caused wildfires.

The NLDN, which has been used operationally for several decades, consists of 113 sensors across the continental United States and has a reported flash detection efficiency of cloud to ground flashes between 90–95%, with spatial errors that are typically less than 500 meters for the flash data used in the study.

The researchers found, of lightning-caused fires that grew to more than 4 km² (988 acres):

50% reported the same day
71% reported within 3 days
73% reported within 5 days
77% reported within 7 days

Holdover fires that are not reported for days or weeks after the lightning occurs can be problematic for land managers. Shortly after a thunderstorm has left the area, fire detection efforts are often ramped up and may continue in that mode for a few days. Fires that smolder in duff or under snow and suddenly grow can be unexpected. Firefighting resources that may have been staged in anticipation of emerging fires could be released or assigned to active incidents, complicating efforts at quick initial attack with overwhelming force.

Authors of the paper: Christopher J. Schultz, Nicholas J. Nauslar, J. Brent Wachter, Christopher R. Hain, and Jordan R. Bell.

Interview with Sara McAllister of the Missoula Fire Sciences Laboratory

Sara’s research focuses on the fundamental physics of wildland fire.

Sara McAllister
Sara McAllister, left, receives award for Early Career Fire Science. IAWF photo.

After the Fuels and Fire Behavior conference in Albuquerque, New Mexico last week I had the opportunity to sit down with Sara McAllister who had just received an award for an Early Career in Fire Science. She talked about how it felt to be selected for the award, her study of fire on spacecraft for NASA, researching how fires burn in New Zealand, and setting stuff on fire for a living at the Missoula Fire Sciences Laboratory.

The video can also be viewed on YouTube.