12/06/2018

Introduction to the Wildland Urban Interface

By Tyler Velten


The Landsat 8 satellite caught this image of the Camp Fire on Nov. 8. The town of Chico can be seen in the lower left corner of the image. (Photo Credit NASA/Joshua Stevens with Landsat data from the U.S. Geological Survey)

California’s fire season has finally come to a close leaving many communities reeling from multiple catastrophic events in both Northern and Southern California. News media is quick to report on the tenuous situation many towns like Paradise, Malibu, Santa Barbara or Napa Valley face with respect to warmer, drier conditions. Wildfire events are not new in the western United States and as a result, state and local officials have implemented an array of mitigation and prevention measures meant to suppress any fire event. But as illustrated in an insightful interactive article by Ash Ngu and Sahil Chinoy of the New York Times (To Help Prevent the Next Big Wildfire, Let the Forest Burn), our communities will need to learn to embrace fire as a vital natural occurrence replenishing and strengthening the ecology of California’s forests and Oakland savannahs. Using prescribed burns to remove low underbrush and thinning younger trees, will make it increasingly necessary for designers to understand and apply appropriate materials and planning measures to prevent loss of life and damage to structures. 

For the purpose of this post, I felt it necessary to share a few resources useful for understanding the Wildland Urban Interface (WUI, pronounced Woo-eee). The following diagrams are excerpted from a variety of organizations.

The wildland-urban interface exists along a continuum of wildland to urban densities. Different WUI types can be correlated to development patterns which transition across zones, similar to the transect model. Source: Community Planning Assistance for Wildfire. 

Cal Fire 100’ Defensible Space Brochure describing an ideal spatial organization of landscape features across a property

Diagram: Wildland Urban Interface Construction Reference Guide. A great starting point for basic building details.

Through observing a slew of fire events over the past 2 years from Santa Barbara to Napa Valley, I have been amazed at the live-time fire tracking made available by various national and state organizations like CalFire. The following photos reflect a series of satellite mapping tools available for following the progress of specific fires.

Map illustrating Butte County’s Camp fire spreading over 5 days. Each color corresponds to the growth of the fire during successive days

Left: Screen Capture from GeoMac.gov Wildland Fire Support showing status of the Camp fire on Nov. 9. Right: Flight Radar screen capture showing Calfire’s 747 Supertanker delivering approx. 20,000 gallons of fire retardant over Paradise.

Live satellite imagery describing fire boundaries and active hotspots. Upper left: SF Fire Tracker. Upper Right: GeoMac.gov Wildland Fire Support. Bottom: Google Earth

Back fire used to burn underbrush leaving mature oak trees preserved

Useful Links:

Wildland Urban Interface

CalFire Building Materials Listings

Historical changes to Wildland Urban Interface