The wildfire mitigation plan for the area where the Marshall fire ripped across a suburban landscape on Thursday hadn’t been updated since 2010, predating heavy population growth in the area.

The plan, managed by the Rocky Mountain Fire Protection District, includes evacuation routes for the area, the designation of subdivisions in hazardous locations and places where proactive mitigation work should have taken place, all of which were 11 years out of date.

The area where the Marshall fire burns straddles the edge separating some of the most prone-to-burn areas of the state and more urban areas where wildfire risks are lower. And while the wildfire spread from house to house through neighborhoods, leaving thousands of Coloradans to deal with tragic loss, it mostly followed wildfire risk predictions.

To the west, in the Front Range mountains of the Boulder Open Space & Mountain Parks, wildfire risk is considered very high, according to U.S. Forest Service wildfire hazard potential data.

Nearly 1,000 structures confirmed lost in Marshall fire; 3 people missing, feared dead

Northwest of where the fire burned, most of Boulder is largely considered to be “non-burnable,” in terms of wildfire risk. The same is true to the east and northeast of the fire’s scar, in Broomfield and the center of Louisville.

And although three-quarters of the area burned by the Marshall fire is classified by the same data as a “moderate” wildfire risk or less, on the western edge, where the fire began, a combination of powerful winds moving east and “very high” wildfire risk zones combined to devastating effect. About one-sixth of the area burned by the fire was considered “non-burnable” by the federal estimate.

Why the Marshall fire was so devastating

Like much of Colorado’s Front Range, the area saw significant growth in the past 10 years, increasing in population by 17%, according to census data. 

What it’s like to evacuate a hospital: As the Marshall fire bore down, so did baby Claire

A Gazette investigation from August 2021 found fewer than one out of every six of the 242 wildfire protection plans in Colorado were updated or created in the last five years. Roughly half of the plans are older than 10 years.

Colorado, unlike some other western states, does not require wildfire mitigation plans to be updated over regular intervals. In Idaho, for example, counties must update their protection plans at least every five years and state officials annually review the plans to determine areas eligible for federal grant funding for mitigation work.