Escalating Wildfires in the Western U.S.

This article relates to Deep Creek

On June 5, 2013, lightning struck dead spruce trees 15 miles south of Pam Houston's ranch, sparking what would become known as West Fork Complex – one of the largest wildfires in Colorado history. West Fork Complex eventually consumed over 100,000 acres in Colorado and became one in a long and growing list of recent wildfires that have ravaged swaths of the Western U.S.

Wildfires in this area are on the increase, whether measured as a count of large fires, the number of acres burned, or a count of states setting records for single wildfire size. A few data points summarize this trend:

• Over the past 30 years, forest fires have quadrupled in Arizona and Idaho; and doubled in California, Montana, New Mexico, Oregon, Utah and Wyoming.
• The number of cumulative U.S. forest acres burned between 2005 and 2013, at approximately 65 million, was over twice the acreage burned between 1985 and 1994, at 30 million.
• Since 2000, more than half of the Western states have experienced their largest wildfire on record. California set a record for its largest wildfire in 2017, then broke the record again in 2018.

Several sources point to multiple and converging causes that directly contribute to the escalation of wildfires, but one of these is acknowledged as the primary, driving factor: the increased temperatures brought on by climate change.

Some of the direct factors cited include:

• Increased temperatures in spring and summer: Overall, temperatures are increasing. However, temperatures in the Western U.S. are increasing much faster than they are globally. Since 1970, the average annual temperature in the Western U.S. has increased 1.9° F, which is about twice the pace of overall worldwide temperature increases.
• Longer fire seasons: The average fire season in the Western U.S. lasted five months in the early 1970s. Today, fire seasons in the same geographic area are over seven months long.
• Earlier snowmelt: Scientists can identify the onset of spring snowmelt by monitoring streamflow gauges. In the Western U.S., with some location variability, the onset of the spring snowmelt is occurring between one and four weeks earlier now than it was in the late 1940s.
• Beetle outbreaks: Warmer temperatures mean that beetle populations can survive the winter and reproduce more frequently. These outbreaks lead to substantial tree deaths, which fuel wildfires. Unprecedented mountain pine beetle outbreaks have affected high-elevation communities, and bark beetles have harmed more than 43 million acres of forests in the Western U.S.
• Fire management practices: The extent to which firefighting practices affect wildfires is still in debate. While some evidence shows that fire suppression tactics reduce the number and frequency of large fires, there is also evidence to suggest that in the long term, intense fire suppression may result in larger fires because of built-up fuel, such as trees and brush. An MIT study published in 2013 highlights this dilemma, showing how well-funded – but shortsighted – suppression efforts take resources away from more holistic and longer-term preventative efforts.

These factors, though listed and described here individually, are interconnected and reinforced by each other. Rising temperatures lead to an earlier snowmelt. Drier conditions lead to the spread of tree-killing insect infestations and the increase of wildfire fuels.

The escalation in wildfires isn't limited to the Western U.S.; research shows that this is a global trend. The factors listed above stem from the complex interplay of forces under the larger umbrella of climate change. According to "Western U.S. Wildfires and the Climate Change Connection," a fact sheet published by World Resources Institute: "No single wildfire can be attributed to climate change. However, research shows that climate change is increasing the duration and severity of wildfires in certain regions, and is expected to continue doing so in a warmer world."

West Fork Complex wildfire courtesy of The Denver Post

Filed under Nature and the Environment

This "beyond the book article" relates to Deep Creek. It originally ran in February 2019 and has been updated for the January 2020 paperback edition. Go to magazine.

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