USA: Compound atmospheric drivers of the catastrophic 2025 Los Angeles urban firestorm

This article investigates the unprecedented fire disaster that destroyed over 16,000 structures and caused 31 fatalities. Urban firestorms are a growing hazard in fire-prone regions worldwide due to increasingly dry vegetation and expanding populations at the wildland-urban interface.

The article finds that event was driven by a rare "jet-forced Santa Ana" wind subtype featuring an amplified upper-level ridge over the West Coast and retrograding trough over the central/eastern U.S., producing extreme northerly flow, large-scale subsidence, and mountain wave activity that impeded aerial fire suppression. Our analysis shows how upper-level atmospheric support can drive surface fire weather, compounding hazard in even well-developed areas. This underscores the importance of aligning long-range prediction with operational preparedness and communication strategies in California's variable hydroclimate.