FEMA is monitoring the region's dams and has seen evidence that some have been "compromised."

The deluge has already killed at least 13 people and left entire communities under water.

Catastrophic flash floods are likely in the Carolinas and Appalachians through early next week.

More than 20 inches of rain have drenched the region, and the total may reach 40 inches in some areas.

The storm could affect as many as 48.6 million people in the region.

Hurricane Florence made landfall near Wrightsville Beach Friday morning as a Cat 1 storm bringing catastrophic flooding.

Dozens of explosions and fires left at least one person dead and 13 injured and displaced 8,600 customers.

Based on history, here's what each storm category is capable of.