Emergency crews and residents scrambled Friday as Helene — the hurricane downgraded to a tropical storm — overwhelmed the Lake Lure dam in western North Carolina, causing damage and erosion along its structural supports.

A mandatory evacuation was ordered Friday morning after local officials notified the National Weather Service that a dam failure was imminent.

By late Friday afternoon, water had crested the dam, but it was continuing to hold despite the structural damage, according to Josh Kastrinsky, a spokesman for the N.C. Department of Environmental Quality.

Some erosion was also spotted on the left abutment, where water “is flowing uncontrolled,” Kastrinsky said. An engineer was expected to inspect the dam late Friday or Saturday and determine the scope of the damage and needed repairs, he said.

The dam, built in 1925 and 1926, is a tourist and recreational destination for the rural county. It also harnesses the Broad River and two creeks to power a hydroelectric plant producing electricity for Duke Power Co. from two hydroelectric turbine generators.

Dam workers typically lower the water in the lake by as much as 8 inches below the normal lake level before big storms, according to a document posted on the town’s website. The town manager approves lowering the lake by more than that amount, it notes.

Workers use three flood gates to release excess water, but once the lake reaches 992.6 inches, the dam overflows, the document says. At that point, the docks on the lake “are underwater and boat tops have been crunched in boathouses,” it says.

Gauges operated by the National Oceanic and Atmospheric Administration reported the Broad River was nearing 992 feet Friday morning as Helene brought historic flooding to Rutherford County and the surrounding region.

At 9 a.m. Friday, town officials notified the Rutherford County Emergency Management office about the pending dam failure, saying water from the lake was expected to top the dam before 10 a.m.

Sirens were activated to let residents in low-lying areas below the dam know about the pending failure, Rutherford County emergency officials said in a Facebook post.

“Evacuations have occurred from the Dam to Island Creek Road,” they said. “Evacuation sirens are sounding downstream of the Dam. Emergency personnel are working with the structural engineers and are going house to house to ensure all citizens have been evacuated.”

The danger from water overflowing the dam would be largely to homes near the Broad River, which flows southeast of the dam. The flash flood warning for Rutherford County was expected to remain in place until at least 2 a.m. Saturday, the NWS reported.

Emergency shelters have been opened at Lake Lure Town Hall on Memorial Highway and the Rutherfordton Presbyterian Church on North Washington Street in the town of Rutherfordton, they said.

The town has known about problems with the aging dam since a 2018 study that recommended millions of dollars in repairs and upgrades.. The work is underway, according to town updates posted online.

The evacuation was expected to displace many residents in the largely rural county, who emergency officials earlier on Friday urged to stay in their homes due to trees and power lines blocking roads across the county.

Blocked roads also forced local fire departments to suspend road clearing operations and EMS crews to stop responding to non-life-threatening calls until conditions improved, officials said. Kastrinsky said nearly 30 roads in the dam’s flood zone were being evacuated at 11 a.m. Friday, and counties downstream were alerted that the situation could require more evacuations later.

Helene made landfall late Thursday night in Florida’s Big Bend, where maximum sustained winds were 140 mph, according to the National Hurricane Center.

Buncombe County also issued a mandatory evacuation order for people along the Swannanoa River, from the North Fork Reservoir to Biltmore Village, because of water cresting the spillway. Other parts of the county were also urged to evacuate.

The story will be updated.

This story was originally published September 27, 2024, 12:58 PM.