Fire Tornado path, Australia. Credit: research led by Rick McRae
We have previously written about events described as “fire tornadoes”, but research led by Rick McRae in Australia has us convinced that those should be more accurately called fire whirls, not tornadoes. We were never very comfortable using the term “fire tornado” for those events, but it has become common and we were not aware, until now, that a phenomenon many times more powerful existed.
Fire tornado documentation, Australia. Credit: research led by Rick McRae
Mr. McRae documented what was unquestionably a real fire tornado that occurred near Chapman, ACT, Australia during the McIntyres Hut Fire January 18, 2003.
Researchers had speculated about the ability of a fire to produce a tornado, but this is the first documentation of the creation of a true tornado by the convection column of a large fire.
In a video interview (scroll down and view the second video) and in a paper published October, 2012 in the journal Natural Hazards, he described a fire tornado as occurring over a vegetation fire, a process now known as the phenomenon of “pyro-tornadogenesis”. Under certain conditions, a fire can cause a pyro-cumulus cloud to form, which is not in itself unusual over a large fire. If the cloud continues to build, it can generate lightning, rain, and hail, much like a conventional large thunderstorm. And large thunderstorms can sometimes propagate a tornado, which is what happened over the McIntyrres Hut Fire.
Mr. McRae’s research determined that the fire tornado was moving across the ground at 30 kph (19 mph), had horizontal winds of 250 kph (149 mph), and vertical winds of 150 kph (93 mph).
Aftermath of a fire tornado, showing 12-15 meter tall trees broken off 2-3 meters above the ground. From research led by Rick McRae.
Dr. Jason Sharples, also associated with the research, described the differences between a fire tornado and a fire whirl:
Tornadoes are associated with thunderstorms and as such they are anchored to a thundercloud above, and are able to sporadically lift off the ground. Fire whirls, on the other hand, are anchored to the ground and do not require the presence of a thunderstorm.
A new series of four short films helps citizens of the Rocky Mountain West understand how scientists study the impact of fire on ecosystems.
The films document a National Science Foundation-funded project called Wildfire PIRE – http://wildfirepire.org – an international partnership among Montana State University, the University of Colorado, the University of Idaho, the University of Tasmania (Australia) and the University of Auckland (New Zealand) along with other universities and agencies in the U.S. and abroad.
In 2010, researchers from the U.S. first traveled to Tasmania and New Zealand to collect data on the impacts of wildfire. Using tree ring cores and columns of mud drawn from lakes, the researchers can piece together the history of fire in different landscapes.
The data from the Southern Hemisphere will also help researchers make predictions about the impacts of fire in the Northern Rocky Mountains.
David Bowman, PhD
One of the four films is titled The (un)Luck of the Draw: Understanding Bushfire in Tasmania, and discusses how the disastrous fires of 1967, referred to as the Black Tuesday Bushfires, affected this island south of the Australian mainland (map). They were the most deadly fires that Tasmania has ever experienced, leaving 62 people dead, 900 injured and over seven thousand homeless within the space of five hours. They followed a very wet spring which produced a great deal of new vegetation growth. Then on a dry, windy February day, dozens of controlled burns, or “burn offs” were fanned into life, along with some other accidental ignitions, burning 2,640 square kilometers (652,360 acres).
In the video, David Bosman, PhD, from the University of Tasmania talks about the 1967 Black Tuesday Bushfires and the fact that it could happen again. Here is a portion of what he says in the film.
…When you know that 1967 happened, and you can see the legacy of it, and you know the terror and the shock it did to this community, and then you know a lot about fire as I do, and you see it’s very, very vulnerable, it’s basically surrounded by flammable bushland.
I’m afraid, and I’m surprised at how afraid I am.
In the deck there’s a card called 1967 Or Worse, and one day the card’s going to be dealt.
The scary thing is we don’t know how often these cards are in the deck. If we get something ’67 or worse, we could burn a quarter of the island down in three hours, and that means thousands of people will die. And I’m afraid of that.
You have to wonder… is there a deck of cards for the northwest United States with one of the cards called “1910 Or Worse”?
The other three films in the series can be found HERE.
The video features Thomas Swetnam, a tree ring expert, and fire historian Stephen Pyne talking about the history of fire in the Southwest, and how fire suppression has changed the forests.
Experimental next generation wildland firefighter clothing. Photo by Ken
Researchers are field testing two upgrades for wildland firefighters — new specifications for fire resistant clothing and fireline lunches. Both of these topics are near and dear to the hearts of firefighters. If the clothing does not fit, or binds, or is too hot, or tears, it can make a 16-hour shift seem like 160 hours. And if the lunches they carry to the fireline suck, they may not get the nutrition and energy they need to combat the fire.
Clothing
The Department of Homeland Security has distributed for field testing 1,000 sets of next-generation fire-resistant clothing for wildland firefighters.
Personnel from the California Department of Forestry and Fire Protection (CAL FIRE), the U.S. Forest Service, and 11 local California fire departments that are fighting ongoing wildfires will test the new equipment. The Science and Technology (S&T) Directorate division of the DHS is conducting this wear trial in partnership with the U.S. Army Natick Soldier Research, Development & Engineering Center’s National Protection Center.
According to the DHS, the next generation of personal protective equipment will improve radiant thermal protection; reduce heat stress; improve form, fit, and function compared to existing garments; and meet National Fire Protection Association (NFPA) 1977 and 1975 standards.
The prototype garment system includes undergarments, socks, shirts, uniform pants, tactical pants, and over pants. The system has a shelf life of five years, allows for rapid donning in three minutes or less, is compatible with existing equipment, and accommodates the 5th to 95th percentile of male and female firefighters.
Lunches
For the last couple of years a new specification for lunches that firefighters carry onto the fireline has been tested. Reports are that there will be different configurations for the lunches that camp slugs dedicated individuals that work at the Incident Command Post are provided, versus the high-calorie meals given to firefighters.
Past studies of sack lunches found that they contained between 1,600 and 2,000 calories, while a Meal Ready to Eat (MRE) is loaded with 2,841 calories. The experimental fireline lunches used in 2011 had about 2,000 calories. We have heard that the new lunches are a little pricey, running between $20 and $24 each.
This year the new experimental fireline lunches have been spotted on at least two fires in California, the North Pass Fire on the Mendocino National Forest, and the Shockey Fire on CAL FIRE’s Monte Vista Unit in San Diego County. The photo below is an example of one of these lunches found on a fire a few weeks ago.
A recent study funded by the Joint Fire Science Program conducted by researchers at the University of Oregon analyzed the effects that large wildfires have on the local economy. Using Bureau of Labor statistics, they evaluated on a county level the labor market trends of western US counties from 2004 to 2008 to identify differences between counties that experienced wildfires where the Forest Service spent more than $1 million and counties that did not experience large wildfires. They also analyzed where and how fire suppression funds were spent.
The researchers found that generally, local employment and wages in a county increase during large wildfires, and economic disruptions from large wildfires are outweighed by the economic impact of the suppression effort in the short term.
In addition, they concluded:
Large wildfires lead to longer-term instability in local labor markets by amplifying seasonal variation in employment over the subsequent year. This is particularly true in sectors such as tourism and natural resources.
On average, the Forest Service spent six percent of wildfire suppression funding in the county where the fires occurred. Amounts of local spending varied from zero to 25 percent.
Local capture of suppression contracting is important because it helps mediate labor market effects. However, the ability of rural and resource-dependent counties to capture suppression expenditures appears to be limited.
The researchers provided an example of how funds were spent on the Cold Springs fire which was north of Yakima, Washington in Yakima County. The fire burned approximately 7,000 acres in July, 2008.
The total expenditures on the Cold Springs fire were $14 million. It started in sparsely-populated Yakima County, but less than 1 percent of the funds were spent there. However, six percent of the funds were spent in adjacent Klickitat County where the closest population centers are located.
Some of the results of the researcher’s work can be found here. More will be posted on their site later in 2012.
There are at least 39 published studies about the effects of bark beetles on wildland fire behavior. With such a bounty of government-funded work, you could hope that we would have some definitive answers, but unfortunately, while there is some agreement among the studies, there is substantial disagreement on some key issues, including the impacts of beetle-caused tree mortality in key areas such as fire behavior during the red needle phase, which is typically one to four years after a beetle attack.
This was one of the conclusions in a recent study that analyzed 39 other published works about the effects of pine beetle mortality. It is titled Effects of bark beetle-caused tree mortality on wildfire, and was written by Jeffrey A. Hicke, Morris C. Johnson, Jane L. Hayes, and Haiganoush K. Preisler.
The chart below is from their paper.
The author’s confidence in the conclusions reached about torching potential and active crown fire potential for the first ten years was low, but it is probable that active crown potential would increase for the first four years after mortality and then decrease dramatically. Torching potential would probably increase.
Surface fire properties, defined as reaction intensity, rate of spread, and flame length, would likely increase, but the confidence in the prediction for the first four years was low.
The authors pointed out that changes in fire behavior following a pine beetle outbreak…
…may only occur under some environmental conditions. For example, effects may be manifested during intermediate wind speeds (Simard et al., 2011) or in moister conditions, such as earlier in the fire season (Steele and Copple, 2009). Past controversy on this topic can be partly reconciled by this consideration of more specificity about study question, time since outbreak, and fuels or fire characteristic when describing results.
Our view of the research
It would be helpful if all of these parameters and studies could distill the conclusions into one index, which I will call Resistance To Control (RTC). Simultaneous increases in surface fire, torching, and crowning would result in more RTC. But it becomes more complicated to characterize when, for instance, crown fire potential decreases to near zero, while surface fire intensity and torching increase. Long distance spotting is a firefighter’s biggest headache and makes fires almost impossible to control, at least at the head. Crown fires are the major culprit for long distance spotting, but surface fires and individual or multiple tree torching can also create spot fires. And all of this varies, of course, with the weather. Strong winds can make ANY fire very resistant to control as long as the fuels are continuous.
If a person leaps to the possibly incorrect conclusion that all of the fire behavior parameters shown in the chart above are accurate, including the sections with low confidence, then RTC would increase one to four years after a beetle outbreak, and then would probably decrease since the crown fire potential would dramatically decline. Surface fires, including those with some torching, can be more easily controlled using tactics, sometimes with aerial support, such as direct hand line construction, hose lays, indirect line construction with burnouts, and backfiring from out ahead of the fire. When crowning is the primary method of fire spread, you usually have to wait for either the weather or the fuels to change. Air tankers and helicopters dropping fire retardant or water can be more effective when the fire is confined to the surface, as long as firefighters are on the ground to take advantage of the temporary slowing of the rate of spread, and if the wind is not too strong.
With apologies to the authors of this very good research paper, I took the liberty of adding a Resistance To Control variable to their chart:
And of course the authors of the paper included the familiar phrase, “more research is needed”, which is a mandatory section in every research paper.
The authors, who are employed by taxpayers, arranged to have the government pay a fee to have their paper published by the for-profit Elsevier corporation which is headquartered in the Netherlands. But thankfully, this time the USFS also published it on their U.S. Government web site where taxpayers can access it at no additional charge.
If you believe taxpayer-funded research should always be available to taxpayers freely over the internet, go to the White House web site and sign the petition. (Update Jan. 23, 2013: you can still read the petition at the site, but it is closed to new signers.)
