What If Ignitions Are Not Suppressed?

What happens if forest fire ignitions are not suppressed? It’s a tough experiment to perform, but some old Forest Service data may help answer. In 1923, the Forest Service published an analysis of fires in 12 California national forests (excepting southern California) that ignited between 1911 and 1920. The data include suppression costs, which are a good proxy for suppression effort. Recall that 1910 was the “Great Fire,” which ushered in the era of Forest Service fire suppression. In 1911 fire suppression was almost non-existent with costs on the 12 forests totaling $18,746. That’s $450,000 in today’s dollars. Compare to 2015’s $500 million spent by the Forest Service suppressing fires in California (even more in 2017), and the numbers show the Forest Service puts about 1,000 times more effort into suppressing fires today than it did in 1911. In 1911 there were no air tankers, no fire engines, and few roads into the national forests. In sum, 1911 is a pretty good proxy for what happens when ignitions are not suppressed.

So what did happen to ignitions in 1911? Click on the table above: 70% remained smaller than 300 acres, while 30% exceeded 300 acres. [“C” fires are those greater than 300 acres]

19 thoughts on “What If Ignitions Are Not Suppressed?”

  1. Very interesting analysis. Thank you for sharing this.

    While interesting, I’m not sure it is all that applicable. It doesn’t take into account the changes in Forest vegetation and climate since 1911, which according to many studies would lead to larger and more intense fires without suppression. Also, it doesn’t take into account changes in the social environment. While we may focus on fire acreage, most publics care more about how wildfires affect their property, preferred recreation areas, and air quality. Just looking at acreage can hide that the social costs of larger wildfires are much greater now than at anytime in the past. Exponentially so compared to 1911.

  2. This is intriguing. But the population of CA in 1911 was a tiny 2.377 million. In 2016, it was 39.25 million and growing, with 13 million estimated to be living in the fire zones. As the fires over the last decade have demonstrated, there is a tight link between this urbanized sprawl and wildland that makes it hard to imagine not suppressing ignitions, at least in these densely built up areas. Been thinking about some of these interconnections: http://tupress.org/blog/la-is-burning

  3. The question posed is hypothetical, of course. In planning terms, it’s the “no action” baseline from which to evaluate fire suppression policy alternatives. Since the Forest Service doesn’t do any fire suppression/management planning, it’s also a question the FS is loathe to ask or answer.

    The question’s answer will also vary from place-to-place and time-to-time. An important caveat for the early 20th century in California — it was unusually wet then. Western Washington today may be more typical of what California was 100 years ago.

    It should come as no surprise that most ignitions remain small. In the western states about half of ignitions are caused by lightning, which tends to strike where it has struck before, i.e., in well-burned locations such as ridge tops. These are natural fuel breaks.

  4. A good example of “what if” can be seen in the Chetco Bar fire this last summer.
    – Ignition source = Lighting
    – Previous fires had burned in the area of ignition during the past two decades. Several fires had overlapping footprints over the area.
    – The fire was looked at and the call made by the Forest Supervisor to monitor and not take direct suppression action.
    – 40 days later the town of Brookings and Harbor were threatened and thousands of people evacuated, 26 structures destroyed, 16,000 acres of private land and 40 million feet of private timber destroyed.
    – $61 million spent, most of it after it blew off of the USFS lands and threatened human life & property.

    Great idea! Let’s look at the 2 Billion spent and analyze the tactics used by the USFS vs State and private. If the general public is satisfied with blackened recreational areas and wanton waste of our public resources, let’s spend the summer backing fire from the boundaries into the national forests and national parks. It’ll cost less. It’ll reintroduce fire (regardless of unnatural fuel loadings) and protect private land and resources……

    There will always be numerous fires that do little damage and may be beneficial to the environment, but we don’t have managers that can predict which ones will stay small. The technology still doesn’t exist that can stop a fire, burning an acre every 4 seconds, on demand or stop a wind event from occurring. The land is not just public and has higher values, to many, than letting it burn to a sterile crisp. Of course we can continue to change the severity rating to convince the public that a fire that “only kills all the trees” but doesn’t sterilize the soil is a low severity fire.

    The economic and health impact to entire regions may be putting a damper on the whole fire is good idea, but by all means lets keep suggesting the idea it is getting peoples attention and forest management may actually regain momentum.
    Once again GREAT IDEA!!!!!!

  5. There are many important factors not accounted for. Decades of fire suppression and humans living in western States are two HUGE issues that have a MAJOR effect on the idea of ‘letting ignitions burn’. Then there’s also the fact that, currently, 84% of all US wildfires are human-caused. Ignoring these issues doesn’t make them go away. Comparing today’s wildfires with the fires of 100 years ago is not a valid comparison.

  6. Thanks for posting this – interesting. The same pattern is seen when you analyze fire size compared with ERC. The fires that get big and cause the most damage are the ones that occur under 97 percentile weather conditions where suppression efforts are ineffective. Putting out fires that burn under more moderate conditions is just kicking the fuel problem down the road until an ignition occurs under more extreme conditions.

    We need to do a better job of planning for how to use wildfire as a tool to help us meet our fuel mitigation goals. We need to identify areas that have low likelihood of transmitting fire into the WUI, prep fuels were appropriate with strategically placed timber projects and then allow wildfires to burn. We aren’t putting out the problem fires (we can’t) only those that would do good.

    We can and should be doing a lot more work to prep the landscape with timber projects but we will never be able to manage at a scale that will have any impact on landscape level wildfire behavior. The economics don’t pencil out. We can however use treatments as a bridge to allow us to use fire to work for us and at scales that have the potential to make a difference.

      • There was not a wind event that occurred between Aug 21-23 when the fire made its largest runs (Avg wind speed between 5-8 mph). However the energy release component for those days (ERC = 74) was within 97 percentile for the region and there was a Haines index of 6. Those are not conditions where I would think fire managers would be interested in using wildland fire use.

        • It’s no surprise that the Rim Fire was mostly terrain driven, pushed by breezes, both in the mornings and in the afternoons, using the river corridor as a conduit.. Add to that the ample fuels and lack of fuelbreaks, as well as “column collapse” (which did generate big winds). Normal summer weather data always favors good burning conditions, especially when drought is in force.

    • PF. Are you saying ” What if you started with where would WFU generally work? where would it not work because of communities, highways, etc.”. Then you could treat with PB, or mechanical plus PB, those “WFU buffer areas.” This might end up being similar to WUI fuel treatments on the landscape, or the SPLAT/SFA approach or not. Do you know if anyone is exploring these ideas?

  7. This seems obvious, but don’t the agencies at least have a fire management/suppression strategy that responds to local fuel conditions and long-term weather forecasts? That would result in letting more fires burn in the years/seasons and places with the least risk of escape. And if they are getting it wrong, doesn’t that improve the process going forward? (I confess ignorance about this kind of planning.)

    • The fire managers on the Chetco Bar fire where from elsewhere and little or no knowledge of local conditions.
      “East winds?” is that a problem one asked.

      • This is one reason why these kinds of contingencies should be thought through beforehand and documented for whomever ends up being in charge. But the initial attack and monitoring strategies should normally be up to local officials. Still, they should have some guidance ahead of time for the specific area and weather. I’ve assumed this is all in the burn “prescription.” But maybe that part of the planning process needs a little more daylight.

    • They do have such a thing, but a lot of fire fighting these days is political – especially if there is the potential to degrade air quality, reduce tourism (which can be a big economic engine in many places), etc. Even though the Biscuit Fire was doing some good work, there was enormous political pressure to “put it out”. The Iron 44 incident in California a few years ago where many firefighters were killed in a helicopter crash was the same thing – enormous political pressure to put the fire out resulted in firefighters working in areas at great expense for little to no use due to the political pressure to put the fire out asap.

  8. There are policies that allow for the theoretical practice of wildland fire use (e.g. https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsm91_057365.pdf) but there is 0 incentives for any FMO to make that decision. From a risk avoidance / self preservation stand point unless there is a top down policy that generates an incentive structure to do otherwise – all wildfires that occur under mild weather conditions will be put out asap. No one is rewarded for responsibly managing fuels only slapped when they are in charge when a fire event that ends up in the textbooks occurs.

    • PF- WFU seems to occur, as well as safety “corralling” of fires here in Colorado. Are things different where you work?

      ?? Here’s a WFU from 2003 http://archives.durangotelegraph.com/03-07-10/quick_n_dirty.htm

      Here’s one from last summer https://www.fs.usda.gov/detail/sanjuan/news-events/?cid=FSEPRD547929

      ” “The Beaver Creek fire might not be fully contained until Oct. 21 — 121 days after its ignition. On Tuesday, 250 firefighters remained assigned to the incident. The blaze’s growth, mainly limited to the rugged terrain in the Mount Zirkel Wilderness where it is not being actively fought, is expected to slow and eventually end with the first sizable snowfall.

      A similar burn this summer is the Hayden Pass fire, southeast of Salida, which consumed dead spruce over about 16,562 acres. Crews used similar tactics to the Beaver Creek fire: keeping firefighters out of dangerous dead trees and engaging flames indirectly by building bulldozer lines far away — sometimes a few miles — from flames.

      The Hayden Pass fire, too, is still burning and was last listed as 60 percent contained.

      “We just cannot be putting our people in an area where all these dead trees could fall on our people or compromise their escape route,” said Jay Esperance, who served stints as incident commander on Beaver Creek and then Hayden Pass just after. “Putting line directly on the fire was just not an option.””


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