A powerful storm with an atmospheric river threatens to bring life-threatening flooding and debris flow from Los Angeles wildfires burn scars. The atmospheric river is forecast to unleash heavy downpours and wind on areas charred by last month’s fires,

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.