Areas charred by last month's wildfires in Southern California now face a new threat from a powerful, but fast-moving Pacific storm. Here's what you need to know about this threat.

A strong Pacific storm with an atmospheric river will continue to pummel California with a threat of flooding rain as feet of snow piles up in the Sierra Nevada through Thursday night. Of particular concern is heavy rain raising the risk of flooding and debris flows in wildfire-scarred parts of the Los Angeles Basin.