Visiting Alaska on Tuesday to highlight the dangers of climate change, President Barack Obama summoned up powerful images of the hundreds of wildfires that have burned across the state this summer: "More than five million acres in Alaska have already been scorched by fire this year—that's an area about the size of Massachusetts."
The Alaska megafires have helped make this an unprecedented wildfire season. Fires raging across the American West have set records for size and property damage, badly stretched firefighting resources, and cost the lives of three firefighters. So far this year, according to the National Interagency Fire Center, eight million acres have burned nationwide, well ahead of the past decade's average of five million at this point. And states such as California still have a couple of months to go in their typical fire season.
Two underlying conditions have stoked these fires: a western drought that's stretching into its fourth year and high temperatures that are unprecedented—2014 was the warmest year on record, and so far 2015 has proved even hotter. The result has been a tinder-dry region unusually vulnerable to lightning strikes or human-caused fires.
To keep track of current wildfires and to place them in a larger context, my collaborators and I have created an interactive map of fires in the United States. It tracks wildfires reported by GeoMAC, a federal clearinghouse of fire information run by the U.S. Geological Survey, as well as past wildfires going back as far as 2003.
Users can see where wildfires have burned in the U.S. each year, click on a fire for further details, then drill down to watch an animation of how the fire's perimeter changed. Once they've zoomed in, users can move around the detailed fire map to see nearby fires from the same year. In all, the database contains nearly 20,000 fires from 2003 to the present, which have collectively burned 87 million acres—about 136,000 square miles, or more than the area of New Mexico.
Every hour the map updates current fire perimeters, as they become available from regional and state fire-management agencies through GeoMAC. The data doesn't include information on what percentage of a fire has been contained or on the suspected cause. But many fires have links to their matching page on InciWeb, a multiagency website that compiles public information on current fires, which can include photographs and more maps.
Wildfires Are Predominantly a Western Phenomenon
Because of temperature, drought, and weather conditions, wildfires in the United States mainly occur in the West, although the number and size of fires vary considerably from year to year. In the Midwest, prairie fires—like those shown in the spring of 2014—are often prescribed burns intended to keep grasslands healthy.
Is climate change responsible for the heavy toll that wildfires have exacted? Evidence is mounting, as Laura Parker wrote recently for National Geographic: "Rising temperatures exacerbate drought, spread beetle infestations, and melt the snowpack earlier."
Some of the intensity of recent wildfires can also be attributed to the decades of fire suppression that allowed an unnatural buildup of fuel in some areas. Though that policy has changed, its legacy remains and still fuels more intense wildfires. in the form of forest conditions that fuel more intense wildfires. Moreover, the pressure to protect homes has grown as communities spread ever deeper into lands that were once wilderness.
The book may soon be closed on 2015 in Alaska, where the remaining fires finally seem to be dying down, but as President Obama pointed out in his address, that state’s fire season is now more than a month longer than it was in 1950. And as the magazine High Country News reported recently, some western fire managers are contemplating a fire season that lasts most or all of the year.
As part of our ongoing collaboration with EcoWest visualizations, the interactive wildfire map is a first step toward a deeper analysis of western wildfire trends. In the coming months, we'll extend the database to include fires back to 1984, using detailed analysis from the Forest Service-USGS Monitoring Trends in Burn Severity project, and we'll include more analysis of long-term fire trends in the American West. If you have questions or want to share comments on the maps, please visit vis.ecowest.org or email us at firstname.lastname@example.org.
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