Hurricane Florence was downgraded to a tropical storm as of 5 p.m. ET Friday, the National Hurricane Center (NHC) said, with maximum sustained winds of 70 mph.

The storm claimed at least four lives on Friday, tearing through North Carolina with torrential rain, flooding and 90 mph winds. Over half a million homes and businesses were without power.

On Friday afternoon, Wilmington, North Carolina Police Department confirmed that a mother and infant were killed when a tree fell on their house. Officials in Pender County, North Carolina also confirmed that a woman with a medical condition died when first responders were not able to reach her due to fallen trees blocking the road. The governor's office reported that another person had died while plugging in a generator.

The White House said in a statement Friday that President Trump plans to visit the affected areas early to the middle of next week, "once it is determined his travel will not disrupt any rescue or recovery efforts." North Carolina Governor Roy Cooper said later that day that President Trump's visit can be arranged at an "appropriate time."

@NWS: As of 5PM #Florence is now a tropical storm, still causing life-threatening conditions to eastern parts of North and South Carolina. Falling trees and power lines, extreme flash flooding, and storm surge in rivers and inlets continue through tonight.

Florence was expected to swamp almost all of North Carolina in several feet of water, Gov. Roy Cooper told reporters.

The National Weather Service (NWS) said as much as 7 inches of rain had fallen overnight in some coastal areas, and as much as 40 inches could fall in isolated areas, including in Virginia. Water level at the Cape Fear River in North Carolina reached an all-time high on Friday, according to the NWS.

Florence is crawling slowly toward the west at near 3 mph and was expected to head west-southwestward through Saturday, forecasters said. The slow movement and life-threatening storm surges are expected to add to the misery.

"It's going to be a long time before you see some of this water level come down," said NHC Director Ken Graham.

In Myrtle Beach, South Carolina, government officials reported around noon that over 13,000 homes are without power, and "emergency responses have been halted until storm conditions allow for personal to respond safely." Virtually all businesses are closed, CNBC's Contessa Brewer reported from Myrtle Beach.

Wilmington, North Carolina Chamber of Commerce CEO Natalie English told CNBC that "the worst is probably yet to come." However, English believes that local business will "be able to get things back up and running" quickly after the storm passes.

@suvCBS: Flooding next to Cape Fear River in Wilmington, NC #HurricanceFlorence

The long period of winds are driving the storm surge inland, up several rivers in North Carolina, where 7 feet of flooding or more is expected as far west as Greenville, potentially even breaching parts of Interstate 95.

"This storm will be a marathon vs. a sprint. In addition to the ongoing, dangerous storm surge and flash flooding, will be a long-term river flood threat WELL INLAND as very heavy rainfall continues to fall in the coming days," the NWS said in a tweet.