South Carolina flooding
A communal worker walks at a flooded street in downtown Charleston, SC on October 03, 2015. Much of the US southeast was under water Saturday, deluged by rains from Hurricane Joaquin, with forecasters predicting more historic flooding in coming days for the already waterlogged region. AFP/Getty Images

The National Weather Service issued emergency warnings for “dangerous and possibly life-threatening” flash floods in parts of South Carolina Saturday. Parts of the state saw over a foot of rain and parts of the state saw rainfall records broken.

Heavy rains battered much of the East Coast Saturday and Sunday, causing power outages and traffic accidents which have left four people dead since Thursday.

The storms are the result of a confluence of extreme weather events: Hurricane Joaquin over the open Atlantic and a second weather system connected to it. Joaquin is not expected to hit the U.S., but, topical moisture associated with it is contributing to heavy rainfall, particularly in South Carolina.

Saturday afternoon's high tide in Charleston -- about 8.29 feet -- was the highest measured there since Hurricane Hugo over 26 years ago, the Weather Channel reported. Combining with torrential rain, major flooding up to waist deep was seen in parts of the South Carolina Lowcountry.

President Obama declared a state of emergency in the state Saturday, ordering federal agencies to coordinate disaster relief efforts, and assist state and local authorities in responding to the floods.

Flooding has shut down the historic center of Charleston and residents were seen using kayaks and paddle-boards to navigate the streets Saturday.

"Where we normally are dealing with flooding for a few hours, we're dealing with it in days here,'' Charleston Police Chief Greg Mullen told the Associated Press. Authorities have opened shelters in some coastal counties, and health officials warned people not to swim or play in the flood waters.

As South Carolina residents braced to ride out the storm, up to 500 residents were evacuated in coastal Brunswick County, North Carolina, that state's governor told CNN. Flood and flash flood watches are posted from Georgia to Delaware through at least Sunday.