A wave of ‘toxic floods’ triggered by a powerful Pacific storm will sweep communities devastated by deadly wildfires. California and Pacific states are on alert for inundating downpours as a rapidly deepening cyclone rages off the west coast.

Rain has finally returned to wildfire-scorched Los Angeles — but now officials are warning flooding and landslides could wreak more chaos on the battered city along its “burn scars.” The National Weather Service issued a flood watch for the area from 4 p.