Two catastrophic floods in early 2017 and 2023 devastated California, causing billions in damage and forcing mass evacuations. These events occurred during La Niña conditions, which typically bring drier weather.

Scientists are now exploring the role of atmospheric events originating from the Arctic in triggering these extreme flooding incidents. The unusual pattern suggests a complex interplay between polar and subtropical climate systems.

The floods highlight California's vulnerability to unexpected climatic shifts and underscore the need for enhanced flood management strategies and infrastructure resilience.