The devastating wildfires that have ravaged Southern California erupted following a stark shift from wet weather to extremely dry weather — a phenomenon scientists describe as hydroclimate whiplash.
New research shows these abrupt wet-to-dry and dry-to-wet swings, which can worsen wildfires, flooding and other hazards, are growing more frequent and intense because of human-caused climate change.
“We’re in a whiplash event now, wet-to-dry, in Southern California,” said Daniel Swain, a UCLA climate scientist who led the research. “The evidence shows that hydroclimate whiplash has already increased due to global warming, and further warming will bring about even larger increases.”
The extreme weather shift over the last two years in Southern California is one of many such dramatic swings that scientists have documented worldwide in recent years.
Unusually wet winters in 2023 and 2024 nourished the growth of brush and grass on hillsides across the region, and then came the extremely warm and rainless weather since spring that has left desiccated vegetation throughout the Los Angeles area.