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The fuels dilemma and Western wildfires

When I was getting certified as a wildland firefighter in 2002, they taught us that fire behavior is based on three basic factors.

First, weather: not just the temperature, humidity, and wind at that moment, but also the climatic conditions over the preceding months and years. All else equal, if it’s hot, dry, windy, and you’re in a drought, you’d expect more extreme fire behavior.

Second, topography: drafty canyons, south-facing slopes exposed to the desiccating sun, and other natural features can encourage burning. Fire travels faster uphill, our instructors cautioned us, but firefighters move slower.

Third, fuels: the type of vegetation, its volume, its moisture content, and its continuity on the landscape. As a fire travels from grasslands to woodlands to dense forests, its personality can change radically.

The first two factors–weather and topography–are out of our control, putting aside the fact that we are changing the weather via climate change and loading the dice toward more fire-friendly conditions in the American West.

What we can directly influence are the fuels. We can break the natural cycle of wildfires by suppressing both human- and lighting-caused blazes, allowing the fuel to build up. We can mechanically thin and intentionally burn areas to reduce the amount of fuel available to future wildfires. We can go so far as to cut down all the trees and pave over a place, thereby eliminating the possibility of a wildfire (or a natural ecosystem).

Tracking fuels treatment to tame Western wildfires from EcoWest on Vimeo.

Fuels dilemma

Today, the American West is facing a fuels dilemma. The graphic below shows the condition of fire regimes across the country. Red illustrates areas where wildfires may be significantly altered from their historic behavior, yellow shows areas that are moderately altered from historic conditions, and green marks where conditions are near historical norms. This data is from 2000, but things probably haven’t changed much since then.

Fire regime: departure from historic conditions

I’ve created slides like these to describe the fuels dilemma in a PowerPoint you can download at the bottom of this post. The presentation explains how the policy of fire suppression has disrupted the natural fire regime in many parts of the West. I’ve also analyzed federal statistics on the number of acres thinned and burned, both in the slide deck and on this dashboard page, but the government’s reporting on fuels treatment is lacking and I’m still in search of better data to characterize this crucial issue.

Fuels treatment

The graphic below distinguishes between a couple of different types of fuels treatment. The first distinction is between activity taking place within and beyond the wildland-urban interface. Known by its acronym, the WUI is where property and residents are at greatest risk of wildfires. The second distinction is between thinning with chainsaws (“mechanical”) and prescribed burns (“fire”).

Fuels treatment on federal lands

The total acreage has been climbing in recent years, but the government only reports this data through 2009. I haven’t been able to find anything more current, but would welcome any suggestions from readers. The data source appears to have been created as part of the George W. Bush administration’s Healthy Forests Initiative but not continued by Barack Obama’s administration.

As of 2009, the federal government was treating an increasing number of acres, but it’s critical to remember that these totals are small relative to the size of the problem. Some 190 million acres of federal land face an elevated risk of catastrophic wildfire, according to one widely used estimate from the U.S. Forest Service (see here for technical report).

I was also struck by the considerable amount of thinning taking place outside of the WUI. Proposals to cut down brush and trees right around vulnerable communities often have the backing of environmental groups, but as these thinning projects move farther into the backcountry, they tend to face more opposition, especially if sizable timber harvesting is part of the equation.

Prescribed burns

On a per acre basis, prescribed fires are much less expensive than mechanical thinning projects, but conditions have to be just right to set a prescribed fire so that it doesn’t turn into a disastrous wildfire. That’s happened occasionally in the West, such as the 2000 Cerro Grande Fire in New Mexico and the 2012 Lower North Fork Fire in Colorado that killed three people. Many in the public remain skeptical or outright opposed to prescribed burns because of the risks and smoke.

The graphic below shows that the number of acres burned in prescribed fires was increasing for a while, but the national total is just a couple million acres annually. (This time series, from the National Interagency Fire Center, is part of their annual report and looks like it will continue.)

Acres burned in prescribed fires

Wildland-fire use

The federal government used to report on instances of “wildland fire use,” essentially letting wildfires burn rather than suppressing them. This strategy is still practiced today when fires are in a wilderness or other remote area and not posing a significant threat to property and people. The graphic below shows the number of acres burned in these types of fires, by agency, but the feds stopped reporting this statistic in 2008.


Acres burned in wildland fire use

Looking ahead

In places like the Southwest, there’s pretty broad agreement among scientists, land managers, firefighters, and conservation groups that additional thinning in the WUI and increased prescribed burns could mitigate–but not eliminate–the risks of catastrophic fires destroying homes. The data I’ve found suggest there’s been a slight upward trend in such fuel treatments, but the overall totals are small and are likely to remain so in a time of fiscal austerity. Letting nature do the work for us would obviously be less expensive, even ecologically preferable, but the proliferation of homes in fire-prone landscapes has made fire suppression an imperative across much of the West.


Data on thinning comes from this report, part of a cooperative effort between the Interior and Agriculture departments. The information on prescribed burns and wildland fire use are from the National Interagency Fire Center.

This story from HowStuffWorks has a good discussion of the three key factors that explain fire behavior.

The Yarnell Fire disaster has generated some solid coverage of the wildfire issue. See this piece by Felicity Barringer of The New York Times on the rising number of homes in the WUI and this op-ed in the Arizona Republic by Don Falk of the University of Arizona. I’m quoted briefly in this story by Amanda Paulson in the Christian Science Monitor.


Download Slides: Wildfire FuelsDownload Slides: Wildfire Fuels (10.96 MB pptx)
Download Notes: Wildfire FuelsDownload Notes: Wildfire Fuels (1.43 MB pdf)
Download Data: Wildfire FuelsDownload Data: Wildfire Fuels (344.64 kB xlsx)

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EcoWest’s mission is to analyze, visualize, and share data on environmental trends in the North American West. Please subscribe to our RSS feed, opt-in for email updates, follow us on Twitter, or like us on Facebook.

Arizona firefighter disaster could be pivotal moment

The shocking deaths of 19 firefighters yesterday in Arizona is a grim milestone in the history of wildland firefighting. Will the Yarnell Hill Fire also be a watershed event in how this nation approaches wildfires?

Sadly, it often takes a national tragedy to raise awareness of problems and force action on solutions.

We know wildfires are getting larger, more people are living in the fire-prone wildland-urban interface (WUI), and climate change will only make the problem worse.

What remains to be seen is whether the disaster will lead to changes in how the nation approaches the wildfire issue. Will it lead to more funding for hazardous fuels reduction and prescribed burns? Will it spur more regulations on development and building practices in the WUI? Will it change how wildland firefighters do their work and make fire managers more risk averse?

A historic tragedy

Looking back over the past century, I think the Yarnell Hill Fire ranks up there with the Great Fire of 1910 (see Stephen Pyne’s Year of the Fires  and Timothy Egan’s The Big Burn) and the Yellowstone Fires of 1988 (see Rocky Barker’s Scorched Earth) as defining moments in the history of U.S. wildfires. The 1910 inferno led to a massive increase in fire suppression; the Yellowstone blazes resulted in greater appreciation of fire’s benefits for many Western ecosystems.

The loss of 19 firefighters in one incident is actually a historic event for all of U.S. firefighting, not just the wildland form. It’s the greatest loss of life since 9/11 and it’s tied for sixth on the all-time list. Notice in the graphic below that almost all of these incidents happened decades ago (this data, from the National Fire Protection Association, has slightly different numbers for wildfire deaths than what the National Interagency Fire Center reports).

Deadliest incidents for U.S. firefighters

A growing problem

While the details from yesterday’s burnover are just emerging, we’ve known for many years that a tragedy like this could happen. We’ve had so many bad wildfires over the past decade or so that it seems the American public and media have become desensitized to hearing that hundreds of homes have been destroyed or hundreds of thousands of acres are ablaze.

The loss of 19 firefighters, however, is anything but normal and hard to ignore. The cynic in me says it may take a huge civilian death toll to really elevate the issue in the national consciousness.

Here are four of the key points that emerged from our research on wildfires:

1)      Wildfires are generally getting bigger

The graphic below shows an upward trend in the average size of U.S. wildfires since 1990. This is very high-level national data, but in another post we provide more detail on the increasing size and intensity of wildfires in the West.

Average size of U.S. wildfires

2) Many fire-prone ecosystems are out of whack

Decades of fire suppression in forests, woodlands, and grasslands that frequently burned under natural conditions has led to an excess of fuel in some areas. The map below shows that the natural cycle has been degraded in nearly all U.S. ecoregions, according to an analysis by The Nature Conservancy.

Condition of natural fire systems

3) More people are living in vulnerable wildland-urban interface

The map below shows where homes are most at risk from wildfires in Arizona. As the West’s population has risen, so has the number of people living in these higher-risk areas. Learn more about the WUI in this post.

Arizona WUI map

4) Climate change will exacerbate problem

Scientists have already found that the warming experienced over the past few decades in the West has led to an increase in wildfire activity. A 2006 paper in Science (graphic below) concluded that “large wildfire activity increased suddenly and markedly” starting in the mid-1980s, with most of the change due to a warming climate rather than fire suppression. Higher temperatures led to a thinner snowpack that melted earlier in spring, leading to more-flammable conditions in summer and a lengthening of the wildfire season by an average of 78 days.

Westerling et al graphic


We have more analysis and data on our main fire page and on dashboards that cover fire trends, suppression, firefighters, ignition, fuels, and the WUI.

Wildfire metrics send a clear signal that this problem is getting worse, especially in places like Arizona, but solutions are anything but simple. There’s no quick fix for forests and woodlands that are ecologically out of balance due to a century of fire suppression. There are already millions of homes in vulnerable locations and only so much that homeowners can do. Some local communities have taken big strides toward reducing their vulnerability and discouraged building in the WUI, but there is political resistance in the West to statewide mandates.

Fighting wildfires will always be an inherently perilous business, but perhaps the Yarnell Hill disaster will force the public and policymakers to confront this increasingly dangerous issue, evaluate the options, and take action.


Download Slides: Wildfires in the American WestDownload Slides: Wildfires in the American West (37.85 MB pptx)
Download Notes: Wildfires in the American WestDownload Notes: Wildfires in the American West (6.42 MB pdf)
Download Data: Wildfires in the American WestDownload Data: Wildfires in the American West (2.65 MB xlsx)

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EcoWest’s mission is to analyze, visualize, and share data on environmental trends in the North American West. Please subscribe to our RSS feed, opt-in for email updates, follow us on Twitter, or like us on Facebook.

A century of wildland firefighter deaths

[6/30/2013 UPDATE: see this post for more details on how the deaths of 19 firefighters in the Yarnell Hill Fire rank historically]

I’m sorry to say that some wildland firefighters are likely to die in the coming months. Over the past decade, an average of 18 people have been killed each year while trying to suppress U.S. wildfires.

I’ve created a dashboard to track fatalities among U.S. wildland firefighters and put together a short presentation that you can download at the bottom of this post along with the data.

As we discuss in our fire slide deck, the Western wildfire season is getting longer and fires are burning more intensely in many places, so I was curious whether there had been an uptick in the number of firefighter fatalities. There is, in fact, a slight upward trend in deaths, but that may be due to an increasing number of firefighters deployed, rather than the job becoming riskier.

More than 1,000 killed

Wildland firefighting remains a dangerous business, with at least 1,030 people killed in the line of duty since the Great Fire of 1910 in the Northern Rockies. The government reports no deaths for the subsequent 15 years, which I’m assuming is due to a lack of data, and the most recent data available is from 2011.

Wildland firefighter deaths: 1910-2011

Cause of death

The most common way that wildland firefighters die is when they are overrun by flames. Such burnovers account for 42% of all deaths in the database, as shown in the pie chart below.

U.S. wildland firefighters killed: cause of death


The next leading cause is heart attack. Fighting fires by hand is grueling physical work and it’s not unusual to see wildland firefighters in their 40s or 50s. When not fighting fires, many work for land management agencies, such as the Forest Service, Park Service, and Bureau of Land Management.

The other trend that jumps out of this morbid data is the perils of driving and flying around wildfires. There were 288 fatalities related to airplanes, helicopters, and vehicles, or about 28% of the total.

Most deaths in West

Wildland firefighters have died in every state except Massachusetts. Eight of the top 10 states for wildland firefighter fatalities are in the West, with California leading the way by far.

U.S. wildland firefighters killed by state

The map below, from our dashboard, shows the geographic distribution of fatalities.

Wildland firefighter fatalities by state

Inherently dangerous work

I’ve been fascinated with wildland firefighting ever since I was certified, or “red-carded,” in 2002 by the Coronado National Forest, while I was reporting for the Arizona Daily Star (read more about my experiences embedding with crews in this piece for Powell’s Books).

Going through the training and spending a lot of time covering wildfires in the Southwest from 2002 to 2005 gave me the sense that safety is taken very seriously by fire managers and firefighters. But it was also easy to see how inherently dangerous the work is, especially once you add aircraft and fire engines to a dynamic environment that is often smoky, dark, and unfamiliar to the exhausted firefighters struggling to protect life and property.

Data sources

The National Interagency Fire Center maintains data on wildland firefighter fatalities on this page.


Download Slides: Wildland Firefighter FatalitiesDownload Slides: Wildland Firefighter Fatalities (2.23 MB pptx)
Download Notes: Wildland Firefighter FatalitiesDownload Notes: Wildland Firefighter Fatalities (509.56 kB pdf)
Download Data: Wildland Firefighter FatalitiesDownload Data: Wildland Firefighter Fatalities (27.61 kB xlsx)

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EcoWest’s mission is to analyze, visualize, and share data on environmental trends in the North American West. Please subscribe to our RSS feed, opt-in for email updates, follow us on Twitter, or like us on Facebook.