Utah Department of Public Safety

Emergency Management - Utah Hazards - Wild Land Forest Fires

Urban Wildland Interface (URWIN) areas are where wildland areas and residential areas meet and affect each other. Urban areas refer to areas containing structures such as homes, schools, recreational facilities, and transmission lines. Wildland areas refer to those areas that are not urban or in a natural state with little development.

Wild Fire Types

Occluded

Occluded interface, are areas of wildlands within an urban area for example a park bordered by urban development such as homes.

Intermixed

Mixed or intermixed interface areas contain structures scattered throughout rural areas covered predominantely by native flammable vegetation. Salt Lake City has 3008.3 acres of intermixed area within its incorporated boundary with the potential of having a wildfire.

Classic

Classic interface areas are those areas where homes press against wildland vegetation along a broad front. The Wasatch front is a prime example of a classic wildland interface zone. Salt Lake City has 952.6 acres of classic wildfire threat within its incorporated boundary.

Causes and Factors

When discussing wildfires, it is important to remember that fires are part of a natural process needed to maintain a healthy ecosystem. Three basic elements are needed for a fire to occure: (1) a heat source, (2) oxygen, and (3) fuel. Two of the three sources are readily available along the Wasatch front. Major ignition sources for wildfire are lightning and human causes such as arson, recreational activities, burning debris, and carelessness with fireworks. On average 65 percent of all wildfires started in Utah can be attributed to human activities. Vegetation, topography, and weather all affect wildfire behavior.

Wildfire Mitigation

The following mitigation recommendations come from the Utah Living With Fire Committee. These recommendations provide a starting point to making your home "wildfire survivable".

  1. Define and Create a "Defensible Space"
    Defensible space refers to that area between a house and the surrounding wildlands where the vegetation has been modified to reduce the wildfire threat. A defensible space can be as simple as a properly maintained backyard. When creating a "defensible space", consider the type of vegetation surrounding your home and the slope of the building lot. Houses located on sloped lots or where the natural vegetation has a tendency to dry out as the summer progresses, require a larger space. Depending on the slope and vegetation, the recommended minimum "defensible space" will vary from a 30 - foot perimeter for level lots up to a 150 - foot perimeter for sloped lots.
  2. Break it Up
    Interrupt the layers of vegetation to provide for separation between trees and small groups of shrubs. This can be achieved through the use of nonflammable products such as crushed rock or organic mulches that help to retain ground moisture and keep flammable nuisance weeds down. Construction of hard surfaces such as patios, sidewalks, driveways, as well as rock and brick walls also help to slow the spread of flames. Keep some distance between ornamental plantings so that a fire cannot spread from adjacent native vegetation to the structure.
  3. Eliminate Ladder Fuels
    Remove vegetation that allows a fire to move from lower growing plants to taller ones. A vertical separation of three times the height of the lower fuel layer is recommended. This could be accomplished by removing the lower tree branches, reducing the height of the shrub, or both. The shrub could also be removed.
  4. Lean Clean and Green
    This concept means keeping an area free of debris by eliminating the accumulation of dead vegetation such as pine needles and leaves. Plants low growing, non - woody plants that are kept green throughout the entire fire season.
  5. Maintain Your Space
    Keeping your defensible space effective is a continual process. Annually, review these defensible space steps and take action accordingly. An effective defensible space can be quickly diminished through neglect.
  6. Check Your Roof
    Look for signs of debris build - up in gutters and on shingles; remove branches over the roof, under the eaves, and within 15 feet of the chimney. Install a spark arrestor; check the rating of the shingles and replace with a fire proof/resistant type. Homeowners should inspect their roof twice a year to remove these easily combustible items.
  7. Construction and Building Location
    For new home construction, the building site location is critical to reducing fire danger. Locate the building away from ridge tops, canyons, and areas between high points on the ridge. Use fire resistant building materials and enclose the underside of balconies, desks, and eaves with fire resistant materials. Consider installing a sprinkler system within the house to protect your home if you are away and to prevent a house fire causing a wildland fire.
  8. Have an Emergency Water Supply
    In communities where there is an insufficient water supply, homeowners should provide additional personal water storage. This extra water could take the form of an above ground water tank, or even a swimming pool. Make sure to clearly mark all water supplies so that firefighters can locate the source quickly.
  9. Fireproof Your Signs and Access
    Access to your property is important not only to get firefighting vehicles to your property, but also to allow for the safe exit of residents as visibility is reduced during periods of thick smoke. Roads must be wide enough to accommodate emergency vehicles and an alternate route of access is also recommended. If your house is not visible from the main road, make sure your address is clearly displayed on a fireproof sign at the entrance to your property.
  10. Do Emergency Planning
    Planning in advance of an emergency just makes sense. All family members should agree on a "safe area" where they can meet should they become separated during a fire. Planning should include how to secure your residence, what to pack, how to park your car for quick escape, and other important life saving facts.

Additional wildfire mitigation information can also be found at:

[Last Update - Friday, 08-Mar-2013 16:25:54 MST]