Abstract

In February 2024, wildfires in the Valparaíso region of central Chile caused more than 130 deaths and destroyed thousands of homes, making them the country's deadliest natural disaster since the 2010 earthquake. This rapid attribution study assesses the role of human-induced climate change in the fire weather conditions behind the event, using the Hot-Dry-Windy Index (HDWI), which combines maximum wind speed and vapour pressure deficit. The 4-day HDWI of the event corresponds to roughly a 1-in-30-year event in the current climate. Observations (MSWX, ERA5-Land) and CORDEX regional climate models show a small but not statistically significant increase in HDWI to date. This is consistent with the region's known wind-driven coastal cooling, and the result is subject to high uncertainty given the limited number of suitable models. Under 2°C of global warming, the trend towards more dangerous fire weather becomes significant. El Niño shows no significant influence on the index. A vulnerability and exposure analysis finds that impacts were driven largely by land management practices, including the expansion of wildland-urban interfaces and informal settlements and the conversion of native forest to exotic monoculture plantations. The study recommends improved spatial planning, community-based fire prevention and stronger early warning systems.