Originally Published: April 7, 2017 5:58 a.m.
Winter is coming to a close, spring has sprung and we see the lakes full of water. It feels as if we had a good winter rainy season; when in fact it was just an average year. Looking at 2016 and early 2017 we received 16.5 inches and 3.4 inches of rain so far for a total of 19.9 inches. The 100-year average is 19.2 inches; however, the 30-year average is 14 inches so it feels like a good year. As we enter spring, the temperatures start go up, the humidity goes down and the winds get stronger; we are moving into wildfire season. Arizona, fire conditions are most severe in spring and early summer before summer rains and to a lesser degree in fall after the end of the monsoon season.
Based on recent history and experience, much of the Southwest is considered a high-hazard fire environment -- an area that possesses all of the ingredients necessary to support large, intense and uncontrollable wildfires. Yavapai County and the Prescott basin are in the bullseye of this targeted area. An area called the Wildland-Urban Interface (WUI), which is any area where structures and other human developments meet or intermingle with wildland forest and scrub fuels. In Arizona 3 percent of the state land is WUI; however, 45 percent of the population lives in the WUI. Within this hazardous area are individual houses, subdivisions and entire communities where many homeowners are ill-prepared to survive an intense wildfire.
Historically, forests have depended on fire to maintain good health. Fire naturally thins trees and brush, and eliminates dead material. But by fighting wildfires to protect homes and people, this natural process has been altered and vegetation density has increased significantly. The look of our forests have changed dramatically during the past decades, with trees being smaller but far more numerous. When fires occur, the dense vegetation burns more intensely, making it more destructive and dangerous. This build-up of fuel coupled with recent insect and disease outbreaks have greatly increased potential for severe wildfires. Climatic factors such as drought and warmer temperatures also play a major role.
The expansion of subdivisions and other high-density developments in the wildland- urban interface has created conditions under which local fire departments cannot protect all structures during a wildfire. Our ability to live more safely in this fire environment depends on pre-fire activities. These are actions taken before a wildfire occurs and improves the survivability of people and homes. The fire service will ultimately determine which properties they save based on probability of success without risk to life, and maximum property survival.
The National Fire Protection Association has established a National Firewise Communities organization to promote community wide participation in the use of practices that minimize the loss of life and property to wildfire; independent of firefighting efforts. The approach emphasizes community responsibility for planning the design of a safe community as well as an effective emergency response; and individual responsibility for safer home construction and design, landscaping and maintenance. With little or no preparation before a wildfire, communities can be devastated, but, with an action plan and regular attention to community wildfire mitigation, wildfire can occur with little to no lasting effect on homeowners.
Finally, two factors are the primary determinants of a home’s ability to survive a wildfire; the quality of the defensible space around the home and structural fire resistance of the home. Together, these two factors create the Home Ignition Zone (HIZ) where the primary goal is to reduce or eliminate fuels and ignition sources.
Next time we will look at the forest materials, makeup and fire potential.
Paul Scrivens is Firewise Assessor and Committee Member The Ranch at Prescott.