Southern California’s Ring of Fire

By Tom Yulsman | July 23, 2013 8:50 pm
Southern California Ring of Fire

A false-color view of a portion of Southern California captured by the MODIS instrument on NASA’s Terra Satellite on July 18 shows fire scars from five fires in 2013, as well as one from 2012. (Image: NASA)

Torrential downpours have all but doused California’s Mountain Fire, which is now 85 percent contained.

Lightning storms inland of Los Angeles and San Diego as seen from the International Space Station on July 21.  The storms helped douse California’s Montain Fire. Click for a larger version. (Photo: Karen L. Nyberg/NASA)

But as the satellite image above suggests, it’s no time to become complacent. It was captured by NASA’s Terra satellite, and I chose the false color scheme because it emphasizes fire and burn scars. Click on it for a larger version, and have a close look.

In the image, the Mountain Fire is seen burning inland of Los Angeles and San Diego on on July 18. (Center right of the image.) Also visible are reddish scars from previous blazes this summer and spring (and one from last fall). They seem to form a partial ring around one of the most highly developed regions on Earth.

For this early in the summer, there have been an unusually large number of intense wildfires in Southern California. The peak of fire season in this area typically doesn’t happen until much later in summer or even in the fall, when vegetation has browned, and the Santa Anna winds kick in.

There have also been an unusually large number of fires so far in California overall. From the first of the year through July 13, the entire state has experienced 3,719 fires that have burned across 63,701 acres, according to the latest data from the State of California.

That’s quite a few more fires than the five year average for that same time period, which totals 2,428. (Luckily, the total area burned so far is a bit less than the five-year average of 77,504.)

If my sense of geography is accurate, seven counties are visible in the satellite image up top, either in whole in or in part. And within those counties, data from Headwaters Economics, an independent, nonprofit research group, show that there are more than 155,000 homes in close proximity to fire-prone wildlands, meaning they are in the so-called wildland-urban interface, or WUI. (Make sure to scroll down to see two infographics I prepared with more data on development within the WUI in this part of California.)

Although homes and other structures have been destroyed in the fires, including seven in the Mountain Fire, no one was killed. Will that luck hold?

With the driest January through June on record in California, and continuing severe drought in large portions of the rest of the West, there’s little doubt that more wildfire is in store, perhaps a lot more, before the burning season is over. Just as important, the Mountain Fire is only one additional data point among very many in a rising trend of wildfire activity in the West. Much of the region has been warming faster than the globe as a whole. And research has shown that this has combined with an earlier onset of spring to cause a dramatic increase in the largest wildfires since the mid-1980s.

Throughout the West, in fact, wildfires are now two times larger on average than they were just a decade ago.

“It’s not just a matter of perception — fires are bigger, fire season is longer and more intense, and the costs for fighting fires have tripled,” says Ray Rasker, the executive director of Headwaters Economics.

Firefighting costs have skyrocketed for a variety of reasons. Suppression of fires, which are a natural part of ecosystems in the West, seems to have caused a “fire deficit” during the 20th century — less fire in the region than would have been expected based on climate factors alone. But with the buildup of fuels, and continuing climate change, it looks like the deficit is being paid off now in the form of higher wildfire activity. (For more on this idea, check out this story I wrote for the Daily Climate last year.)

But there’s another crucial reason why firefighting costs are skyrocketing: More people than ever are living in or near the WUI.

The result? “Firefighting now consumes 50 percent of the U.S. Forest Service’s budget,” Rasker says.

About 30 to 60 percent of the wildland-urban interface has been developed in five of the counties visible in the satellite image above: San Diego, Riverside, San Bernardino, Los Angeles and Orange counties. So when fires erupt there, risks to homes can be very high — and all-out efforts to protect them are often launched.

The graphics below show just how much of the wildland urban interface is developed in these counties, as well as a few others in this part of Southern California:

The Mountain Fire has been burning in Riverside County, where 28 percent of the WUI is developed. Six homes, one commercial building, and a number of other structures were destroyed. More than a thousand personnel have battled blaze, and 13 governmental agencies — from local fire departments to the federal Bureau of Land Management — have been involved in one way or another. When it’s all over, and firefighting costs will no doubt be well into the millions of dollars.

And that’s just one blaze.

The first one of the year in this region was the Powerhouse Fire (upper left corner of the satellite image), which began on May 30 and ultimately burned more than 30,000 acres. It got started in Los Angeles County, where the WUI contains more than 34,000 homes.

A few days later, the Springs Fire ignited and spread rapidly in the Santa Monica Mountains (also in the upper left corner), ultimately covering more than 24,000 acres. It started in Ventura County. The number of homes in the WUI there totals more than 10,000.

Next up, and in short order, was the Summit Fire (just right of center). It was small but burned very close to the city of Banning in Riverside County, where there are more than 22,000 homes in the WUI. Also in Riverside County was the Hathaway Fire, which got started on June 9.

Down in San Diego County, with more than 38,000 homes in the WUI, the Chariot Fire ignited on July 6. A little bit to the north in San Diego County, the Vallecito Lightning Complex fire began last August. (I include it here because its fire scar is quite noticeable in the satellite image.)

My goal in this post was to document some of the broader context for what has been going on in Southern California in recent weeks. But I’ve got more information to share. So in at least one other post, I’ll look more broadly at the West overall, and delve more deeply into how we’ve gotten ourselves into this fix of rising risk, rising damage, and rising costs. And I’ll share some of Ray Rasker’s ideas for how we can begin to solve the problem.

I’ll leave you with an assignment: Check out the second part of the infographic above, the one showing the percentage of each county that’s developed. If you look at each one, you’ll see that some have not yet developed much at all in the WUI. It’s in those places where a good deal of undeveloped wildland still remains. And it’s obviously there that new policies could potentially have the biggest impact in lowering risks and firefighting costs.

More about that in a subsequent post. So make sure to check back.




ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


See More


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar