Atmospheric rivers, while vital for replenishing water on the U.S. West Coast, are also the leading cause of floods though storm size alone doesn t dictate their danger. A groundbreaking study analyzing over 43,000 storms across four decades found that pre-existing soil moisture is a critical factor, with flood peaks multiplying when the ground is already saturated.

Atmospheric rivers, while vital for replenishing water on the U.S. West Coast, are also the leading cause of floods though storm size alone doesn’t dictate their danger. A groundbreaking study analyzing over 43,000 storms across four decades found that pre-existing soil moisture is a critical factor, with flood peaks multiplying when the ground is already saturated.