Ahead of the storm’s arrival, officials in Southern California distributed sandbags, prepositioned rescue swimmers and told residents to have go-bags ready.

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.

The weather phenomena are common for California winters, but they could cause dangerous debris flows or mudslides in recently burned areas.