Recognizing Fire Risks in the Wildland-Urban Interface

Some 32 percent of U.S. housing units and one-tenth of all land with housing are situated in the Wildland-Urban Interface (WUI), and growth of housing within the WUI is expected to continue. While the degree of risk may vary from one place to another, given the right conditions, wildfire can affect people and their homes in almost any location where wildland vegetation is found.

Even structures not immediately adjacent to wildland vegetation are at risk of damage from wildfire because embers can be transported by wind and ignite vulnerable homes a mile or more away from the flame front. Reducing the loss of lives, property, infrastructure and natural resources from wildfires depends on long-term community action.

Land use decisions, building codes and standards, and other planning and landscaping choices all influence a community’s vulnerability to damage from wildfire. Communities can reduce the risk of such damage by becoming knowledgeable about and engaged in actions to plan and protect their homes and neighborhoods from wildfire. Ken-Caryl has become a Firewise Community to be better prepared to recognize the risks of wildfire and mitigate those risks where possible.

Fire is, and always has been, part of the dynamics of the attractive area in which we have chosen to live. Much of the area within Ken-Caryl falls within the WUI. The risk of wildfire is not isolated to the Valley and the North Ranch, but risks are present in the Plains as well. The Plainview fire in 2006 struck an area north of Golden along Highway 93, and high winds pushed flames through 2,700 acres of grass in just a few hours.

Fire is part of our natural ecology, as history demonstrates that fires have burned periodically throughout the Ken-Caryl Ranch Open Space – most recently in the 1978 Murphy Gulch Fire, which burned right to edge of Ken-Caryl Valley and the North Ranch.

Today, all of the factors necessary to support large, intense and uncontrollable fires remain. What’s different is an increased population with an increase of homes in the “wildland urban interface” areas, sometimes with little regard to fire’s threat. As human activity increases in these interface areas, the incident of fire activity increases as well. This has increased the risks of more and more disastrous fires causing huge losses and amplified the demands on firefighting resources.

There are things you can do to recognize the threat and prepare for it. Every step you take in advance reduces risk to you, your family and your home whether firefighters are available to help protect you or not. Through planning and preparation before a fire event, you can be ready for wildfire.

Wildfire Behavior

To better understand wildfire behavior, three basic components directly affect fire, and these components affect the likelihood of fire starting, how fast it moves, its intensity and difficulty to control.


Dry, hot and windy weather increases the chances of a major wildfire. These conditions make ignition easier, help fuel burn more rapidly and increase fire intensity. High wind speeds can transform a small, manageable fire into a disastrous event. In Colorado these weather conditions are identified as “Red Flag Warning” days, with the potential for rapid growth of a wildfire.


Fuel is a requirement for any fire to burn. In a wildfire, the fuels are usually living vegetation such as trees, shrubs, grasses and dead plant materials. Homes, when in the path of wildfire, will also become fuel. The quantity, size, moisture content, arrangement and other fuel characteristics will influence the ease of ignition, the rate of fire spread, the length of flames and other associated fire behavior.

Topography (Terrain)

The feature of greatest interest is the steepness of slope, as this is among the most influential to fire behavior. The steeper the slope, the faster a fire will spread. The “aspect” of slope, or the orientation of slope to the sun’s direct exposure is another important factor. For example, south and southwest slopes usually have more fires. With north-facing slopes, these will have fewer occurrences of fires but may have greater fuel densities and fire behavior when ignited. Another important feature of the terrain is the presence of “chimneys,” which are steep, narrow drainages that can speed the spread of fire due to preheating and funneling of winds within a localized area.

The best approach to wildfire preparedness involves utilizing the wide range of Firewise practices. The Ken-Caryl Firewise Committee has distributed information on practical steps (landscaping, home construction and design, community planning, evacuation planning, and Ready, Set, Go!) that families can take to reduce their vulnerability to wildfire.

Examples of Firewise techniques for property owners include creating a defensible space around residential structures by thinning trees and brush; choosing fire-resistant plants; selecting ignition-resistant building materials; and working with firefighters to develop emergency plans. Recognizing the risks of wildfire in the Ken-Caryl community is the first step in preparing for wildfire and enhancing the safety of our families and neighbors.

This article appeared in the June 29, 2016 issue of Life at Ken-Caryl.


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