Thursday's Bear Creek Fire renewing concerns of the wildland-urban interface, or WUI, defined as areas where human improvements are built close to or within natural terrain and flammable vegetation. In 2018, the Colorado State Forest Service said about half of all Coloradans live in areas at risk for wildfires, and 2.9 million live in WUI areas, a number that continues to rise. The primary concern in these areas is vegetation density. Homeowners and property owners should pay attention to plants on your property. Lighter density within 30 feet of a structure helps to reduce the chance of a fire igniting. In 2018, several factors contributed to the nearly 50 percent increase over the past five years in numbers of Coloradans considered to be living in wildfire risk zones. One is an overall increase in the number of people living in WUI areas.