And projections show that the West may be in for more large wildfires in the future. Climate models show an alarming increase in large wildfires in the West in coming years, as spring snowpack melts earlier, summer temperatures increase, and droughts occur more frequently or with greater severity.
In Arizona, the current drought, combined with the regional heat wave, has created extremely dangerous wildfire conditions. Three quarters of the state of Arizona is experiencing “severe” to “exceptional” drought conditions, according to the latest U.S. Drought Monitor. In neighboring New Mexico, conditions are even more dire, with about 45 percent of the state experiencing “exceptional” drought, the worst-possible category.
Long-running precipitation deficits, including a below-average winter snowpack, have led to extremely dry soil moisture conditions in Arizona and New Mexico, in particular, and in other states across the West.
In recent years, the Southwest has trended toward drier and warmer conditions, which is consistent with climate-model projections that show that the region may become more arid in the coming decades, due in large part to manmade global warming. In fact, Arizona was the fastest warming state in the contiguous U.S. since the mid-1970s, with average surface temperatures increasing by 0.639°F per decade since 1970.
Other contributors to wildfire trends include the consequences of decades of fire-suppression policies, which have left many forests with large amounts of vegetation to serve as fuel for wildfires. Another factor is population growth, and more specifically, development that has taken place at the edge of areas that have a history of wildfires, known as the “wildland-urban interface.”
Compared to an average year in the 1970s, during the past decade there were seven times more fires greater than 10,000 acres each year, and nearly five times more fires larger than 25,000 acres each year, according to Climate Central research.