The National Hurricane Center says life-threatening, catastrophic flash floods and prolonged, significant river flooding are likely over portions of the Carolinas and the southern to central Appalachians.

The U.S. military "is ready to go all-in," to help with search and rescue and other storm response activities, Lt. Gen. Todd Semonite, commander of the US Army Corps of Engineers, said in a Sept. 14 TV interview..

The Corps said in a Twitter post that day it had 15 active mission assignments from FEMA, including providing temporary emergency power, debris removal, temporary roofing,  assessing infrastructure and water and wastewater system and providing technical assistance for dam safety.

Florence is expected to only slowly weaken during the night on Sept. 14, because it is still near the warm Atlantic Ocean. Convective bands of torrential rains and heavy winds were expected to continue to develop and propagate inland in the eastern and southern portion of the circulation, according to a 5 p.m. statement from the National Hurricane Center (NHC).

Faster weakening is forecast over the weekend as the storm moves westward across the higher terrain of central and northwestern South Carolina. More than 16 inches of rain had fallen in many areas across southeastern North Carolina by evening on Sept. 14.

The NHC says life-threatening, catastrophic flash floods and prolonged significant river flooding are likely over portions of the Carolinas and the southern to central Appalachians from western North Carolina into southwest Virginia through about Sept. 18. In addition to the flash-flood and flooding threat, mudslides are also possible in the higher terrain of the southern and central Appalachians across western North Carolina into southwest Virginia.

Florence made landfall near Wrightsville Beach, N.C., at 7:15 a.m. eastern time Sept. 14, with sustained winds of 68 mph, and gusts of more than 90 mph, according to the NHC. After landfall it crept westward at about 5 mph throughout the day. The town of New Bern, off Pamlico Sound and well north of the landfall of the center of the sprawling storm, was particularly hard hit. Even before landfall, an overnight Thursday 10-ft rise in the Neuse River, due to heavy rains and storm surge, left hundreds of residents trapped and needing rescue by FEMA-dispatched several swift water rescue teams, said Gov. Cooper in a press conference late in the day Sept. 14.

Electricity Outages Extend Inland

Electricity outages extend well inland with more than 770,000 customers without power as of 6 p.m. Sept. 14, according to the North Carolina Dept. of Emergency Management. Utilities said that they expected up to 2.5 million outages in North Carolina. Duke Energy warned it could be weeks before power is restored in some areas. An additional 80,000 outages were reported in South Carolina and about 5,000 total outages were reported in Georgia and Virginia, according to the U.S. Energy Dept. 

While interstates and other major highways through the most affected areas remained open late in the day, NCDOT reported that severe dune erosions overwash on sections of State Route 12 on Hatteras Island would keep that road closed indefinitely.

Duke Energy said on Sept. 16 that 450,000 customers in the two states remained without power, but that it has been restored to about 830,000 customers out of 1.3 million total outages. The utility said that it has 20,000 personnel working on reconnections, including crews brought in from 25 states.

A coal-ash impoundment failed on Sept. 15 at Duke Energy's Sutter coal-fired power plant near Wilmington, N.C. that has been closed since 2013, a spokeswoman confirmed to media. She said about 2,000 cu yd of coal ash was displaced but she could not confirm if any had contaminated the rising Cape Fear River, according to the Asheville Citizen-Times. The company had been excavating the ash to move to another location.

As rain from an expected two-day deluge began falling in South Carolina, the state’s dam regulators completed assessments of more than 260 structures, with 27 identified for continuous surveillance. A spokeswoman for Tennessee-based emergency response contractor Phillips & Jordan told ENR that the firm's contract with the South Carolina Health and Environmental Dept has been "activated for monitoring and maintaining more than 400 high hazard earthen dams." 

SCDOT was preparing to mobilize resources in preparation for expected flooding along the Lumber, Little Pee Dee and Waccamaw Rivers in the state’s eastern regions.

State transportation secretary Christy Hall told reporters late on Sept. 15 that the agency, assisted by county crews and the state national guard, is building temporary dams—one about 1-mile-long and the other 1.5-miles—in the Little Pee Dee, Lynches and Waccamaw rivers to keep traffic flowing on key routes U.S. 378 and 501. She said work would be completed by Monday, Sept. 17.

According to DOT officials, flooding closed a nine-mile section of Interstate-95 in Dilllon County, S.C., that borders North Carolina, with "no passable detours." Also the interstate is closed in North Carolina from state road 82 in Fayetteville to Highway 64 in Nash County, according to reports on Sunday.

Hurricane-generated heavy rainfall in 2015 and 2016 closed major stetches of I-95 in the two states for more than a week, says The State, a local publication and The Charlotte (N.C.) Observer.

The National Weather Service predicted Florence will weaken over South Carolina through Sept 16, then gradually accelerate as it moves northward across the Appalachian Mountains.

The agency estimates that nearly 5 million people will receive more than 10 inches of rain by Sept. 17. With much of that rainfall flowing into tributaries of the Tennessee River, the Tennessee Valley Authority has accelerated drawdowns at many of its eastern storage reservoirs.

Reservoir Releases

Releases from Chickamagua Reservoir near Chattanooga, Tenn., for example, had reached 62,000 cfs, and could increase if needed. “We’re digging a hole to store more water,” explains TVA spokesperson Travis Brickey, who says that the unusually rainy summer had left reservoir water levels as much as 8 inches above normal when the agency began its normal schedule of post-Labor Day releases to make room for winter and spring rainfall.

As precipitation forecasts for Florence came into sharper focus, however, TVA began more aggressive water releases, using spillways at five of nine dams. Among them is the Cherokee Dam in Knoxville, Tenn., where spillway gates were opened for the first time since 1994.

Brickey says the releases are carefully coordinated across the TVA’s network to keep the network in balance. Meanwhile, agency is also working with the Corps of Engineers on flood-control measures for the lower Ohio River, which has been swollen over the past few weeks by rainfall from the remnants of Hurricane Gordon.

Semonite said on Sept. 14 that "the Dept. of Defense is ready to go all-in" to assist with search and rescue and help with the hurricane response.

In a morning interview on the Fox and Friends program, Semonite said that more than 7,000 military personnel were "ready to respond today, mainly on search and rescue."

Semonite added that there more than 4,000 soldiers were located near Fort Bragg in North Carolina and about 83 helicopters were on the scene. "The Army is ready to jump in and respond." 

He also said that through about Sept. 14, a key Corps activity would be to check the condition of dams in the area. "That's probably one of the things we're most concerned about," said, noting that there are about 8,000 dams are in the Carolinas, not all of which are Corps facilities.

Semonite said Corps assessment teams were ready to respond to requests from mayors or other local officials to inspect dams. He added that if the Corps sees any dams that pose risks or show signs of degradation, it has "reaction teams" that can help localities respond.

Asked about the flooding in New Bern, N.C., Semonite said that "with low-level flooding, there's not an awful lot that...the Army Corps of Engineers can do if there are no dams or other structures there." He added, "But we're going to have to see how this water recedes and then go in and be able to react."

The Federal Emergency Management Agency also has tasked the Corps to help provide temporary electric power. If a specific critical facility, such as a hospital or nursing home, has lost power, Semonite says "we've got over 100 generators, right at Bragg, ready to 'flex in,' with other hundreds on standby."

Semonite also said another issue is storm debris. "There's a time here, in a couple of days, [when] we've got to be able to go in and haul all that debris back out, so these...people can get back to their way of life."