(WLTX, AP) South Carolina Gov. Henry McMaster says more than 300,000 people have already evacuated the state's coasts ahead of Hurricane Florence.

McMaster told reporters Wednesday that the storm could bring more rain to the state than 1989's devastating Hurricane Hugo. McMaster has ordered much of the state's coastline evacuated, reversing some lanes of a major interstate to direct all traffic inland.

"If you are in an evacuation zone, you need to leave now," McMaster said.

LATEST FORECAST: Hurricane Florence Tracking Toward the Carolinas

State leaders are urging people who are in low-lying areas to go ahead and leave. McMaster says once the winds pick up, even emergency personnel will have to shelter in place.

"It will be very hard for people to rescue you," McMaster said. "This is a big, big storm, with rain and water that we have not seen before."

Forecasters warned as much as 15 inches could fall in some portions of the state through at least Monday.

LIVE BLOG: Hurricane Florence Latest Updates and Video

The head of the state's National Guard also says the federal government has positioned aid ships off South Carolina's coast and they'll be ready to assist after the storm moves through.

Evacuation Information

There is an evacuation for most of the South Carolina coastal counties. The evacuation order DOES NOT apply to the Midlands

Know Your Zone: Evacuation Zone Information

South Carolina State Emergency Hotline

1-888-246-0133

SCEMD Website

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You can also review the South Carolina Emergency Management Division's checklist for preparation. Again, no need to panic and run out and buy things at the grocery store. But it's just good to go ahead and look at it. There are a ton of good resources there.