The Waldo Canyon Fire, which destroyed nearly 350 homes on the outskirts of Colorado Springs in 2012, illustrated the increased risk of fire hazards in wildland-urban interface zones. Photo by Helen H. Richardson / Getty Images

In a report amounting to a red flag for wildfire danger, the Colorado State Forest Service recently revealed that half of Colorado’s population lives in the wildland-urban interface, where risks are greatest for destruction of life and property during wildfires.

In interface zones, housing development abuts forest and grasslands. The proximity carries inherent risks when dry vegetation ignites and grows into dangerous wildfire, a familiar pattern in a state with a semi-arid climate and intermittent drought.

In a state with 5.6 million people, an estimated 2.9 million lived in interface zones in 2017, according to Colorado Wildfire Risk Assessment data released in November.

Equally notable was the increase: The number of homes in the wildland-urban interface spiked by nearly 50 percent over five years, from 2012 to 2017, the assessment showed.

Illustrating the problem, the Waldo Canyon Fire raged in the foothills northwest of Colorado Springs in June 2012, causing two deaths, destroying 346 homes, and burning more than 18,000 acres. The wildfire was the most destructive in Colorado history – until just one year later. In June 2013, the Black Forest Fire, northeast of Colorado Springs, resulted in two deaths and destroyed 489 homes – an ominous new record – while scorching more than 14,000 acres, according to news reports.

“With the continued increase in Colorado’s wildland-urban interface population, it’s critical for landowners and communities to take actions to reduce their risk and address forest health concerns,” said Mike Lester, state forester and Colorado State Forest Service director.

The new population data are included in updates to the Colorado Wildfire Risk Assessment Portal, or CO-WRAP, an online mapping tool that helps community leaders, professional planners, and interested citizens determine wildfire risk and where forest management actions may achieve the greatest impact to reduce risk. (The tool may be accessed at

The Colorado State Forest Service is a Colorado State University service and outreach agency that contributes to forest stewardship across the state.