Forecasters released a breakdown Tuesday of where and when heavy rainfall this week is expected to hit areas of Southern California left burn-scarred by recent wildfires, raising the risk of potentially dangerous debris flows in those parts of the region.

Residents in burn scar areas should be ready to evacuate if needed. City and county agencies have readied streets for debris flow with K-rails and sandbags, as a storm moves in on Wednesday, Feb.

Another major storm system threatening the West Coast with rain, mudslides and flooding is triggering new evacuation warnings in areas of California impacted by last month's wildfires. CBS News national weather correspondent Rob Marciano has more.