A photo of August 2021 mudslide damage to Interstate 70 released by the Colorado Department of Transportation. (CDOT)
Without a doubt, one of the largest threats to American infrastructure is climate change.
This was illustrated yet again as upwards of 10 landslides ravaged sections of Colorado’s Interstate 70 corridor, closing the Glenwood Canyon portion of the highway indefinitely. This came after weeks of intermittent slides that have exhausted personnel and had a chilling effect on local economies.
Yet despite the impacts, few have sought to elaborate on the relationship between extreme debris flows and the burning of fossil fuels.
This is a grave oversight.
Dismissing the role of climate change in infrastructure resiliency fails to appreciate the inherent relationship between infrastructure and environment. As global temperatures rise, so, too, will the number of extreme events. This places existing structures and byways in new dangers, ranging from some damage to full destruction.
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In the case of mudslides, as wildfires burn bigger and hotter due to rising temperatures and severe drought, ground vegetation of the forest floor is burned off at alarming rates. This creates a layer of dusty ash over bare, scorched soil, resulting in a decreased ability of the soil to absorb water.
While healthy forest floors can hold several inches of water per hour, high or moderately burned areas might only hold one-third of an inch. This results in top layers that can be easily washed away, at least until enough ground vegetation is reestablished — roughly the first year or two post-burn. Meanwhile, even small amounts of rainfall can result in dangerous runoffs, posing great risks to structures and byways located in slide paths. Combined with more intense rainfall — also due to climate change — landslides may occur more frequently and over larger areas with greater force and debris.
This dynamic is consistent with recent events on I-70. Based on post-fire assessments conducted by the Burned Area Emergency Response team, the Grizzly Creek Fire — which was fueled by especially hot and dry conditions last year — burned areas surrounding the canyon. Soil testing revealed that 55% of this area had incurred moderate to high soil burns, leaving the region with unusually high risks of extreme runoffs. Only 12% of the 32,370 acres were estimated to be unburned.
Certainly, mudslides are possible in any canyon so steep — and it’s happened before. However, the size and severity of this particular burn created enhanced risks for severe infrastructure damage. Accordingly, at the recommendation of BAER, mitigation efforts were made.
Shortly after the fire, one large, natural berm was created to protect the most critical infrastructure in the canyon — a mostly hidden command center in the heart of Glenwood Canyon that serves to monitor the interstate. As predicted, less than a year later, some 100,000 cubic yards of debris was diverted with that very berm. John Lorme, the Colorado Department of Transportation director of maintenance and operations, hailed the effort as saving the state millions of dollars and extensive closed highway time — a testament to the role of climate research in protecting infrastructure.
There are, however, limits to our current preventative measures — as evidenced by the current debris damage. During a 47-minute press conference with CDOT, Region 3 director Mike Goolsby acknowledged the lack of radar technology and understanding in predicting slides with enough time to close or protect the highway.
According to the U.S. Geological Survey — the only science agency to exist within the U.S. Department of Interior — much additional research funding and efforts regarding landslides are needed as climate change intensifies. Especially relevant are the needs to better understand debris flow mechanisms, forecasting and mitigation strategies, all efforts that would help safeguard core infrastructure.
One Colorado-based hydrologic engineer, Kelsey McDonough, agrees, adding that some in the private sector may also have access to better, more localized technology. “This could be really useful in a state like Colorado where local knowledge can be utilized to build better regional monitoring and modeling systems than are currently available at the national scale,” she says.
Certainly, Colorado has a number of cutting-edge national laboratories and private companies that may be inclined to help find solutions with the right incentives. Securing these funds is just one of many roles local representatives can play in helping the state navigate the new challenges.
Still, perhaps the most important thing we must do is disentangle the notion that discussions of human-driven climate change during extreme events are signals of political interference. They are not. Climate change is well established in scientific literature, as is its impact to structural integrity. Addressing the role of reducing fossil fuels in related press conferences and articles is therefore necessary to serve the long-term goal of infrastructure stability.
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