Spatio-temporal pattern of California wildfires from 2000 to 2019

Abstract:

Wildfires in California have intensified in recent years, with not only a significant increase in the occurrence but also a startling increase in property losses and casualties, which has aroused great social concern. According to the California Department of Forestry and Fire Protection (CAL FIRE), in nearly 100 years since their record, nine out of the ten largest and most destructive wildfires, and four out of the ten deadliest wildfires occurred in the past 20 years. Therefore, we explored the temporal and spatial distribution of California wildfire from 2000 to 2019 based on CAL FIRE Administrative Units. Moreover, this study selected 13 environmental and social variables related to wildfires to discuss the natural and human factors which have a great influence on the current wildfire behavior. The results showed that California wildfires’ annual occurrence had been generally on the rise in the past two decades, while the total burned area often declined after a peak. Wildfires were most frequent from June to September over a year. In terms of spatial distribution, the Sierra Nevada Mountain and the Greater Los Angeles Area were the hot spots for wildfire occurrence. Naturally occurring wildfires, mainly caused by lightning, were concentrated in Northern California, while human-caused wildfires were relatively evenly distributed across western and central California. Among the natural and social variables related to wildfires over the 20 years, housing density and maximum temperature have the most substantial changes in California, which were the main factors that increase the frequency and risk of wildfires. This study provides a reference for the management of wildfires, the formulation of future wildfire emergency plans, and the planning of future land use in California.