Researchers attempt to quantify how climate change will affect wildfire seasons

Future Very Large Fires wildfires

The projected percentage increase in the number of “very large fire weeks”—weeks in which conditions are favorable to the occurrence of very large fires—by mid-century (2041-2070) compared to the recent past (1971-2000). (NOAA)

Researchers are predicting that beginning 26 years from now the number of weeks in which very large fires could occur will increase by 400 to 600 percent in portions of the northern great plains and the Northwest. Many other areas in the West will see a 50 to 400 percent increase.

If they are correct, the effects of climate change are not generations away. Firefighters starting out today will be dealing with this on a large scale during their careers.

Warming due to increasing greenhouse gas emissions will likely increase the potential for ‘very large fires’—the top 10 percent of fires, which account for a majority of burned areas in many regions of the United States. Climate change is expected to both intensify fire-friendly weather conditions, as well as lengthen the season during which very large fires tend to spread.

The potential for very large fire events is also expected to increase along the southern coastline and in the forests around the Great Lakes, although the number of events along the northern tier of the country should only increase moderately given the historically low potential for these events.

For this study, researchers considered the average results of 17 climate model simulations to examine how the potential for very large fires is expected to change. Future projections* were based on a higher-emissions scenario called RCP 8.5, which assumes continued increases in carbon dioxide emissions.

Along with the elevated potential for very large fires across the western US in future decades, other climate modeling studies have projected increases in fire danger and temperature, and decreased precipitation and relative humidity during the fire season. The increased potential for these extreme events is also consistent with an observed increase in the number of very large fires in recent decades.

In addition, scientists have detected trends toward overall warming, more frequent heat waves, and diminished soil moisture during the dry season. The combination of these climate conditions and historic fire suppression practices that have led to the build-up of flammable debris have likely led to more frequent large fire events.

At this very moment, more than 56 large wildfires are burning uncontained throughout the West, putting homes, lives, and livelihoods at risk. The smoke created by these fires exacerbates chronic heart and lung diseases while also degrading visibility and altering snowmelt, precipitation patterns, water quality, and soil properties. In addition to public health impacts, projected trends in extreme fire events have important implications for terrestrial carbon emissions and ecosystems.

The authors of the study also note that these findings could place a burden on national and regional resources for fighting fires. Fire suppression costs in the U.S. have more than doubled in recent decades, exceeding $1 billion per year since the year 2000, the National Interagency Fire Center reports. The vast majority of that money is spent on large incidents.

climate change predicted fire seasons

The research was conducted by government employees at taxpayer expense, funded by NOAA, the U.S. Forest Service, and two universities. The authors were: Barbero, R.; Abatzoglou, J.T.; Larkin, N.K.; Kolden, C.A.; and Stocks, B. The title: “Climate change presents increased potential for very large fires in the contiguous United States”. It was published in Australia in the International Journal of Wildland Fire (copies available for $25).

We checked with Frames.gov which posts copies of government-funded research, and were told by Michael Tjoelker, “Unfortunately, due to copyright issues we are not able to distribute full text versions of Journal articles.” However, Renaud Barbero, one of the authors, sent us a copy.

Thanks and a tip of the hat go out to Bill.

Share

BlueSky Modeling Framework

BlueSky screen grab

Screen grab from a BlueSky animation.

The U.S. Forest Service has developed a system called BlueSky Modeling Framework using multiple models that when combined in various configurations can enable:

  • the lookup of fuels information from fuel maps
  • the calculation of total and hourly fire consumption based on fuel loadings and weather information
  • the calculation of speciated emissions (such as CO2 or PM2.5) from a fire
  • the calculation of vertical plume profiles produced by a fire
  • the calculation of likely trajectories of smoke parcels given off by a fire
  • the calculation of downstream smoke concentrations.

The image above is a screen grab from a Beta website of an animation of a 3-hour running average of PM 2.5 using modeled fires. (Don’t ask me to explain it any further than that!)

More information about the system is HERE. You can configure your own animation at THIS SITE.

Share

Time-lapse of monitors setting up a fire effects plot

The Fire Effects crew from North Cascades National Park is seen in this time-lapse video filmed over a two-hour period placing fire monitoring plots just outside fire perimeter of the Paradise Fire in Olympic National Park.

The fire that started May 15 in the Olympic peninsula rain forest has burned 1,781 acres.

I wonder to what degree the intensive human activity in the plot while establishing it affects the results.

Share

NASA helping to develop better fire shelters

(Video: fire shelter testing in June, 2015.)

After 19 firefighters were killed while fighting the Yarnell Hill Fire in Arizona in 2013, many people called for better fire shelters, since the shelters used then were not effective in preventing the 19 fatalities.

This January, NASA reached an agreement with the US Department of Agriculture’s Forest Service to test prototype fire shelters made from the space agency’s next-generation thermal protection systems (TPM) materials.

The team of engineers from NASA is developing flexible heat shields that will protect spacecraft from the high temperatures of atmospheric entry under NASA’s Hypersonic Inflatable Aerodynamic Decelerator (HIAD) project. NASA and the Forest Service have found that there are common performance requirements between fire shelters and flexible heat shields that can be used to benefit both organizations.

In September, 2014 small scale testing on 39 material samples began at Missoula Technology Development Center (MTDC). Thirteen materials that showed no obvious shortcomings were sent to Mark Y. Ackerman Consulting in association with the University of Alberta for the first round of third party lab testing. The only materials that had an improvement in the thermal protective performance tests were those that were bulkier and heavier than the current shelter material. Third party test results are being shared with those who have submitted materials for possible improvements.

Prototype shelters were tested for the first time in a forest fire setting in late June, 2015 when NASA’s Langley Research Centre, University of Alberta adjunct professor Mark Ackerman, and the US Department of Agriculture’s Forest Service travelled to Fort Providence in Canada’s Northwest Territories to conduct a series of controlled outdoor burns.

Share

Researchers find insect-killed forests pose no additional likelihood of wildfire

flames wildfire

Photo by Bill Gabbert

As mountain pine beetles and other insects chew their way through Western forests, forest fires might not seem far behind. Lands covered by dead trees appear ready to burst into flame.

However, an analysis of wildfire extent in Oregon and Washington over the past 30 years shows very little difference in the likelihood of fires in forests with and without insect damage. Indeed, other factors – drought, storms, and fuel accumulation from years of fire suppression – may be more important than insects in determining if fire is more or less likely from year to year.

Scientists reached this conclusion by mapping the locations of insect outbreaks and wildfires throughout Oregon and Washington beginning in 1970. Researchers discovered that the chances of fire in forests with extensive swaths of dead timber are neither higher nor lower than in forests without damage from mountain pine beetles.

The same comparison done on forests damaged by another insect – western spruce budworm – yields a different result. The chances of wildfire actually appear to be slightly lower where the budworm has defoliated and killed trees in the past. While the mechanics of such an association are unconfirmed, it’s possible that budworm outbreaks could reduce the risk of wildfire by consuming needles in the forest canopy.

“Our analysis suggests that wildfire likelihood does not increase following most insect outbreaks,” said Garrett Meigs, lead author of a paper published this week in the open-access journal Ecosphere. Meigs is a former Ph.D. student in the Oregon State University College of Forestry and now a post-doctoral researcher at the University of Vermont.

Across more than 49 million forested acres in both states, insects and fires typically affect less than 2 percent of the land in a given year. More forestland is usually disturbed by insects than by fire.

“Most forests have plenty of fuel already,” Meigs said. “Green trees burn, not always as readily as dead ones, but they burn. The effects of insects are trumped by other factors such as drought, wind and fire management.” For example, the 2002 Biscuit Fire, the region’s largest at nearly 500,000 acres, occurred in an area with little tree damage from insects.

“Even if mountain pine beetle outbreaks do alter fuels in a way that increases flammability, the windows of opportunity are too small – and fire is too rare – for those effects to manifest at landscape and regional scales.”

“In the case of the budworm, our findings suggest that there may be a natural thinning effect of insect-caused defoliation and mortality, and it is possible that insects are doing some ‘fuel reduction’ work that managers may not need to replicate,” said Meigs. That possibility needs more research, he added.

These results are consistent with other studies that have investigated the likelihood of fire across the West. For example, a 2015 study published in the Proceedings of the National Academy of Sciences by University of Colorado scientists found that despite extensive outbreaks of mountain pine beetles in the Rockies and the Cascades, fires in recent years were no more likely to occur in beetle-killed forests than in forests not affected by the insects.

Public perception may reflect our experience with starting campfires, said John Bailey, Oregon State professor of forestry and co-author of the Ecosphere paper.

“We choose dead and dry wood for kindling, not green branches,” Bailey pointed out. “A dead branch with lots of red needles is ideal. At the scale of a forest, however, the burning process is different. Wildland fire during severe weather conditions burns less discriminately across mountainsides.”

For managers of forestlands, these results suggest that emphasis needs to be put on fuel reduction, forests near communities and on preserving ecosystem services such as biodiversity and water quality. “Forests will continue to burn whether or not there was prior insect activity,” Meigs and his co-authors write, “and known drivers like fuel accumulation and vegetation stress likely will play a more important role in a warmer, potentially drier future.”

The Ecosphere paper is available at http://dx.doi.org/10.1890/ES15-00037.1.

In addition to Bailey, Meigs’ co-authors included John L. Campbell, Harold S. J. Zald, David C. Shaw and Robert E. Kennedy, all of Oregon State. Funding support was provided by the NASA Earth and Space Science Fellowship Program and the USDA Forest Service.

Articles on Wildfire Today tagged Beetles.

Share

Radiation heat transfer once believed to dominate over convection heat transfer in wildfire spread — study reveals that’s not the case

MSO Fire Lab flame research

Researchers at the Forest Service’s Missoula Fire Sciences Laboratory study how a wildfire spreads, May 21, 2014. Photo by Bill Gabbert.

A new study about the physics of how a wildfire spreads has been completed by government employees, and thankfully it is freely available to taxpayers. A success for Open Access to the products of government-funded research!

The phrase “spreads like wildfire” is well-known but until recent discoveries through experiments conducted by scientists from the Missoula Fire Sciences Laboratory, University of Maryland and the University of Kentucky, it wasn’t well-known how wildfires actually spread. Specifically, it was unclear how radiation and convection heat transfer processes, which both occur in wildfires, are organized to produce wildfire spread. Now, evidence presented in a new study, Role of buoyant flame dynamics in wildfire spread, reveals how flame dynamics that produce and transport convective heat effectively governs the spread of wildfire.

Previous studies focused mainly on radiant heat so little was known about the respective roles of convection and radiation on fire spread and most often the assumption was made that radiant heat was the governing factor. But scientists recently found that the net rates of heat transferred by radiation are insufficient because the fine fuel particles that constitute wildland vegetation cool efficiently by convection until contacted by flame.

As stated in the study, “if radiation itself is insufficient to account for fire spread…convection must provide the explanation.” So a team of scientists, led by Mark Finney of the USDA Forest Service Rocky Mountain Research Station, began looking at flame dynamics.

Utilizing specialized burn chambers and wind tunnels at the Missoula Fire Sciences Lab and the University of Maryland, scientists were able to assimilate and measure flame dynamics. They found this process can correctly scale up to those found in large-scale wildfires. They also conducted outdoor experiments and prescribed fires at Camp Swift, TX. The experiments led to the discovery of previously unrecognized flame behaviors and how those behaviors cause wildfires to spread. They also discovered that flame vorticity (circulations) and instabilities due to the buoyancy of flame gasses, cause wildfires to spread by forcing flames downward into the fuel bed and bursting forward ahead of the fire into fresh fuel (grass, brush, etc.).

“This study opens the door into the little known world of flame dynamics and gets us closer to understanding the complexities of radiative and convective heat and how they affect wildfire spread,” said Finney. The information obtained through this research is significant with the potential to:

  • Improve firefighter safety by providing better training to recognize and anticipate wildfire behavior
  • Simplify the physical principles of wildfire spread that can lead to the development of improved prediction models, and,
  • Improve the ability to mitigate fuel hazards by accurately modeling and describing fuel contribution to wildfires

The team of ten scientists who contributed to this study comes from the USDA Forest Service Rocky Mountain Research Station’s Missoula Fire Sciences Lab – lead scientist Mark Finney, Ph.D., the University of Maryland’s Department of Fire Protection Engineering – lead scientist Michael Gollner, Ph.D., and the University of Kentucky’s Department of Mechanical Engineering – lead scientist Kozo Saito, Ph.D.

Six brief videos supporting the research are available, but you have to download them onto your device in order to view them.

The study is available as a free .pdf download at WildfireToday/Documents.

Share