Broad-Scale Surface and Atmospheric Conditions during Large Fires in South-Central Chile

The unprecedented size of the 2017 wildfires that burned nearly 600,000 hectares central Chile highlight a need to better understand climatic conditions under which large fires develop. Here we evaluate synoptic atmospheric at surface and free troposphere associated with anomalously high (active) versus low (inactive) months area in south-central (ca. 32–41° S) from Chilean Forest Service (CONAF) record 1984–2018. Active fire are correlated warm temperatures, dry conditions, presence circumpolar assemblage high-pressure systems located ca. 40°–60° S. Additionally, temperatures active linked reduced strength cool, onshore westerly winds an increase warm, downslope Andean Cordillera easterly winds. Episodic wind anomalies superimposed on long-term warming drying trends will continue create promote Chile. Identifying mechanisms responsible for determining whether this trend is strengthening due synoptic-scale changes such as poleward shift Southern Hemisphere be critical anticipating future activity