As the already soaked residents of South Carolina struggle to recover Monday from record weekend floods that caused at least eight deaths, meteorologists are warning them the downpour isn't done. Some areas, including the cities of Charleston and Moncks Corner, can expect up to four additional inches of rain Monday, according to the local National Weather Service branch. The forecast prompted authorities to warn people to avoid floodwaters, watch for falling trees and boil drinking water, NBC News reported.

"Stay home. Stay off the roadways," South Carolina Emergency Management spokesman Thom Berry told the Weather Channel. "Don't get on the roadways because you very likely can become part of the problem."

Storms that started Thursday dropped so much water on South Carolina that Gov. Nikki Haley called it a "thousand-year rainfall" event, meaning the amount of rain was so high it's statistically only seen about once every 1,000 years. Some places, like Mount Pleasant, received up to two feet of rain. The conditions, which were exacerbated by Hurricane Joaquin, prompted curfews and desperate warnings of flash floods that could extend for the next three days, USA Today reported.

As of Monday morning, about 20,000 people were without power and 375,000 had been instructed to boil their water. Eight people had died as a result of the weather, with two of them in North Carolina, Reuters reported. "We have property destroyed and lives crushed," state Rep. Kirkland Finlay told CBS News.

The chance of rain in Charleston for Monday hovered around 60 percent, with the rest of the week alternating between partly cloudy and sunny conditions. Even though the rain was forecast to end, the floods remained a threat. "Exceptionally high" rivers could further damage South Carolina into Wednesday -- "even though it will be sunny by then," said NBC News meteorologist Bill Karins.