Ginger Richardson grabs a floating plant during an inspection of a office building on Front Street in Georgetown, South Carolina, Oct. 4, 2015. Randall Hill/Reuters

UPDATE 10 p.m. EDT: The death toll from the South Carolina flooding has reached eight, Reuters reported. At a news conference, South Carolina Gov. Nikki Haley reiterated her warning: "If you are in your house, stay in your house. This is not something to be out taking pictures of."

UPDATE 5:30 p.m. EDT: South Carolina Gov. Nikki Haley Sunday put the death toll from the historic flooding at three, rather than the four earlier reported. Haley at a news conference urged people to stay inside if their homes weren't flooded. "This is an incident we've never dealt with before," she said, CNN reported.

UPDATE 3:15 p.m. EDT: Columbia, South Carolina, Mayor Steve Benjamin announced a Sunday night curfew, running from 6 p.m. to 6 a.m., WIS-TV, Columbia, reported. "We can replace property but we can't replace lives," Benjamin said. "Please stay off the streets and let our first responders do their job."

Original post:

President Barack Obama declared a state of emergency in South Carolina Sunday as historic rainfall caused deadly flash floods and power outages throughout the state. At least four South Carolina residents have died as a direct result of the dangerous weather, which authorities expect to continue through Monday.

About a foot of rain had fallen on Charleston, South Carolina, by Sunday afternoon, CNN reported. Other parts of the state received more than 18 inches of rain, with coastal areas expected to receive at least 8 inches more by Monday. “It’s a historic flood the likes of which we haven’t seen,” Eric Rousey, South Carolina’s emergency management spokesman, told CNN.

State officials have shut down nearly 100 roads and bridges because of the storm, the Wall Street Journal reported. Tens of thousands of people have experienced power outages, and hundreds of others needed to be rescued after being stranded by floodwaters.

At least four people have died on South Carolina roadways since Friday. More than 300 vehicle collisions and nearly 140 downed trees have been reported, South Carolina’s highway patrol told NBC News. Emergency services are stretched thin as countless residents call for assistance. Columbia, South Carolina’s fire department reportedly had a backlog of more than 100 emergency calls this weekend.

The weather system passing over South Carolina is separate from Hurricane Joaquin, the Category 3 hurricane that caused widespread damage in the Bahamas and was expected to make landfall along the U.S. East Coast. But the South Carolina storm has drawn some moisture from Joaquin, CNN noted.

As storm conditions worsened, state authorities urged residents to remain indoors and stay off roadways. South Carolina is experiencing a “one-in-1,000 year rain event,” the Weather Channel reported. Obama’s declaration of a state of emergency means federal resources will be made available in the state.

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