The Wildland-Urban Interface
Mapping Washington State's fastest-growing environment
Washington has always been a place where the land largely dictates how humans can live.
Our waterways define our cities' boundaries,
Our hills and mountains limit the extent of our sprawl.
Known for its beautiful landscapes, many Washingtonians' backyards are also our state's forests,
expansive shrub-steppe,
or its sweeping grasslands.
The WASHINGTON DEPARTMENT OF NATURAL RESOURCES serves Washingtonians across all 39 counties.
All of which contain some WILDLAND- URBAN INTERFACE.
The WILDLAND-URBAN INTERFACE, or WUI, for short, are those areas where
WILDLANDS
and HUMAN DEVELOPMENT (namely, the STRUCTURES we create)
MEET (i.e., neighbors these wildlands) or INTERMINGLE (is found within these wildlands).
A quick note on WILDLANDS: this includes many different types of undeveloped lands!
While most folks may first consider FORESTS (which are indeed included),
Washington's wildlands also include GRASSLANDS
and SAGEBRUSH-STEPPE, to name a few.
For the purposes of this map, WILDLANDS are defined as any area with more than 50% burnable vegetated cover.
Let's take a look at the WUI at the county scale:
Pierce County WUI
is comprised of the following:
- URBAN AREAS
- WILDLAND-URBAN INTERFACE
- WILDLAND-URBAN INTERMIX
- WILDLANDS
- LONG-TERM NONBUILDABLE AREAS
Let's go through each of them individually.
Urban Areas
URBAN AREAS are relatively self-explanatory: they are those areas in Washington with both dense human development, as well as less than 50% vegetative (wildland) cover. These areas are defined by their high density of structures.
As you can see in Pierce County, the urban areas largely coincide with the main cities and towns.
Interface
The INTERFACE is often found along the outskirts of urban area.
The WILDLAND-URBAN INTERFACE is defined as those areas where human development MEETS areas that are covered with more than 50% wildlands.
To be considered INTERFACE, development/structures must be bordered by wildlands on at least one side.
Intermix
WILDLAND-URBAN INTERMIX are those areas where structures intermingle with wildlands. To be considered intermix, a development OR structure must be surrounded on 2 or more sides by wildlands.
INTERMIX is often found between the INTERFACE and the WILDLANDS.
However, as you can see in Pierce County, INTERMIX can also be found in undeveloped/low-density pockets of urban areas.
Wildlands & Long-Term Nonbuildable Areas
As stated before, WILDLANDS are those areas without any structures or human development that also have more than 50% burnable vegetative cover.
HOWEVER, most WILDLANDS could eventually become INTERMIX, INTERFACE, or even URBAN AREAS.
For example, a new single-family home in the woods could make WILDLANDS into INTERMIX, while a new housing development, strip mall, or other series of structures could turn a section of WILDLANDS into INTERFACE.
Because of this, we like to think of WILDLANDS as "Potential future WUI."
HOWEVER, there are certain areas of our state where new structures have little to no likelihood of being built--spaces like National Parks, as well as designated wilderness areas.
These areas are defined as LONG-TERM NONBUILDABLE AREAS. These should NOT be considered "potential future WUI."
These components make up the WUI across all of Washington State:
- URBAN AREAS
- WILDLAND-URBAN INTERFACE
- WILDLAND-URBAN INTERMIX
- WILDLANDS
- LONG-TERM NONBUILDABLE AREAS
Now that we understand what the WUI IS, we need to clarify what the WUI map IS NOT:
The Wildland-Urban Interface Map is NOT a wildfire risk map. Below, we've included a map of the WUI, as well as a wildfire risk map, visualized through the USDA Forest Service Wildfire Hazard Potential data produced by the USFS (hover over the lower left-hand corner for the legend/key):
While the maps DO overlap in some areas, the Wildland-Urban Interface, or WUI, is not the same as wildfire risk.
As such, the Wildland-Urban Interface map can be used as a TOOL to help define wildfire risk, but it cannot be THE TOOLKIT.
HOW TO USE THE MAP
So, if the map is a tool, how can it be used? We anticipate that residents, private homeowners and landowners, city and county planners, emergency management professionals, natural resource agencies and organizations, as well as county fire marshals and building officials will all find this map helpful in decision-making.
Below, we've outlined a few ways this map could be used. Please note that this list is in no way exhaustive -- we expect users will show us a lot of new ways to use this map!
Washington's Wildland-Urban Interface: The Interactive Map and Data
Ready to use the Wildland Urban Interface (WUI) data?
The WUI is available for basic viewing in this web map application:
Do you have your own GIS software/team? The WUI spatial data is available for download here:
As a quick note: We'd love to hear from you!
We hope the Wildland-Urban Interface map will be a living, breathing map that is continually improving. See an area that should be WUI? Don't see your own home in the interface or intermix? Please let us know!
Special thank you!
A lot of people helped to make this WUI mapping project a reality, but a particularly special thanks goes out to Greg Dillon, Eva Karau, and the USFS Rocky Mountain Research Station in Missoula, Montana for providing their methodology, consultation, and support!
