Rescue crews went door to door in South Carolina's capital city Monday morning as officials continued to free residents were trapped by severe flooding that swamped virtually the entire state.

"There's probably around 100 people in the West Columbia area still trapped in their homes," said Wyatt Coleman, West Columbia Fire Chief, in a Monday morning interview with The Weather Channel.

For other parts of the state, residents have been warned that this horrific event is far from over.

"Catastrophic flooding continues," wrote the National Weather Service's Charleston office in a Monday morning forecast discussion. Making matters worse, a wind advisory has been issued for some parts of the Palmetto State, and with all this saturated ground, there's a big fear that trees will blow over, adding another threat for pedestrians and drivers.

The 1,000-year rain event has set records all over the state, flooding entire towns. At least six people have died from the floods in South Carolina since the rain began to fall days ago.

The rain hasn't subsided everywhere yet. In northeastern South Carolina, where areas like Myrtle Beach experienced severe flooding on Sunday, heavy rainfall continued Monday, and officials warned life-threatening impacts would persist into the week.

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\ "The flooding is unprecedented and historical," said Dr. Marshall Shepherd, a meteorologist and director of the atmospheric sciences program at the University of Georgia, in an email to The Associated Press.

The University of South Carolina announced Monday classes will be canceled due to the floods. Parts of Columbia, including the USC campus, lost water service, and plans were being made to deliver bottled water and portable restrooms to the students Monday morning.

City officials have released a statement issuing a boil water advisory to all 375,000 of its water customers, advising them to vigorously boil their water for a full minute at the least. Any ice made from water that was not boiled beforehand should also not be used.

Swift-water rescue teams plucked hundreds of residents from stranded cars and flooded homes all over the state.

"Move to higher ground now. This is an extremely dangerous and life-threatening situation ," wrote the National Weather Service's Charleston office in a Sunday morning flash flood statement.

Officials claim it may take weeks or months to assess all of the closed roads and bridges, including a 75-mile stretch of I-95, the freeway that connects Miami to Washington, D.C. to New York.

Hundreds of roads remain closed Monday across the state; the South Carolina Department of Transportation has a full list here .

Multiple dam breaches were reported Sunday morning in Columbia, according to the city's fire department. On its Twitter page, the department said Arcadia Lake, Forest Lake and Lake Dogwood have been affected by the breaches , and if residents are in a dry place, they should remain there.

The city of Columbia, which reported a new 24-hour record rainfall – 7.77 inches between 11 a.m. Saturday and 11 a.m. Sunday – was placed under a mandatory curfew Sunday night into Monday morning.

Emergency vehicles struggled to navigate the flooded roadways, and in many instances, they were only able to reach victims by boat. In Berkeley County, the U.S. Coast Guard assisted in water rescues , according to WCSC-TV, as more than one family needed to be removed from their homes. Authorities also requested helicopters to aid in rescues because the number of people needing help outnumbered the vehicles that could reach them.

On Sunday, a Coast Guard crew aboard an MH-65 Dolphin helicopter rescued Cristi Mueller and her 15-month-old daughter from the roof of their home in Huger. The mother and daughter were stranded after heavy rain and flooding overtook the house, forcing them onto the roof to escape the water. They were hoisted and taken to Mt. Pleasant Regional Airport and are in good condition with no injuries.

(PHOTOS: Historic Flooding in the South )

Conditions around Charleston improved Sunday to the point that residents and business owners were allowed to enter the downtown area on a limited basis .

In Dorchester County, emergency managers reported at least 100 people had to be rescued at about 3 a.m. EDT Sunday morning from one area. Dorchester Emergency Manager Mario Formisano told The Weather Channel hundreds more likely will need to be rescued, and water rescues could top 1,000 people in the county before the flooding ends.

Nearly 30,000 customers lost power at the height of the storms.

The seawall at Edisto Beach has been breached, resulting in heavy flooding, SCEMD reported Saturday evening, and a state of emergency has been declared for the town.

Multiple shelters have been opened; South Carolina's Emergency Management Division has a complete list here .

(MORE: Coastline Battered by Flooding, High Tides )

Around midday Sunday, flooding was also reported in the Myrtle Beach area. According to local reports, vehicles were getting stranded on flood-covered, impassable roads, and some neighborhood roads were also flooded. City Manager John Pederson was authorized by Mayor John Rhodes to declare a state of emergency for Myrtle Beach . Residents are being encouraged to stay inside and, if driving is absolutely necessary, not to attempt driving through standing water.

Governor Nikki Haley declared a state of emergency Thursday evening in advance of any potential impacts from flooding. President Barack Obama also declared a state of emergency and ordered federal aid to help the recovery in South Carolina.

"This is different than a hurricane because it is water, it is slow moving and it is sitting. We can't just move the water out," said Haley at a news conference.

Charleston store owner Lauren Tuorto told WTVR.com she closed her consignment shop until Tuesday because of the flooding.

“It is impossible to navigate the peninsula right now without a kayak or a monster truck,” she said. “Having weathered plenty of hurricanes in the Out Islands of the Bahamas where my family lives and living in Charleston for 10 years, I have never seen rainfall like this."