Tropical Storm Hilary drenched deserts and flooded roadways in California. Now it’s threatening Oregon and Idaho

Hilary, the first tropical storm to hit Southern California in 84 years, swept people into swollen rivers, toppled trees onto homes and flooded roadways as the massive system marched northward Monday, prompting flood watches and warnings in more than a half dozen states. The National Hurricane Center in Miami downgraded Hilary to a post-tropical storm Monday morning, but warned that “continued life-threatening and locally catastrophic flooding” was expected over portions of the southwestern U.S., along with record-breaking rainfall. There was the potential of flooding in states as far north as...