Winter Storm Fern has exited stage right, but not before wreaking havoc on power grids across the southeastern United States. As of Monday morning at 9 am ET, more than 800,000 customers were still without electricity after Fern pummeled a vast swath of the US with snow, sleet, and ice amidst subzero temperatures.

According to live tracker PowerOutage.com, Tennessee (250,459), Mississippi (161,059), and Louisiana (127,719) have the most outages, followed by Texas (66,665), Kentucky (47,624), and South Carolina (44,114). Tens of thousands of power outages persist in Georgia, North Carolina, Virginia, and West Virginia.

A Deadly, Icy Mess

More than a dozen deaths have been blamed on the winter storm already, and perilous conditions persist through the day Monday, creating “dangerous travel and infrastructure impacts” for days, according to the National Weather Service.

For utilities, that means power poles and lines damaged or broken under the weight of ice. Predictions called for up to a staggering 1.5 inches of ice accumulation in some areas, including northern Mississippi and the western Carolinas. For reference, half an inch of ice (or less) is all it takes to down a power line and trigger widespread outages.

On Sunday, freezing rain slickened roads and brought trees and branches down, imperiling hundreds of miles of the southern US. In Corinth, Mississippi, heavy machinery manufacturer Caterpillar told employees at its remanufacturing site to stay home Monday and Tuesday. In Oxford, MS, police appealed to residents to stay home, and some utility crews were pulled from their jobs overnight.

“Due to life-threatening conditions, Oxford Utilities has made the difficult decision to pull our crews off the road for the night,” the utility company posted on Facebook early Sunday. “Trees are actively snapping and falling around our linemen while they are in the bucket trucks.”

Elsewhere, deep snow — over a foot (30 centimeters) in a 1,300-mile (2,100-kilometer) swath from Arkansas to New England — halted traffic and canceled flights.

President Donald Trump approved emergency declarations for at least a dozen states by Saturday. The Federal Emergency Management Agency had rescue teams and supplies in numerous states, Homeland Security Secretary Kristi Noem said.

Hardest-Hit Utilities and Their Response

Tennessee’s Nashville Electric Service (NES) and Entergy (primarily in Louisiana) remain the heaviest-hit utilities Monday morning. More than 175,000 Nashville Electric subscribers are without power, representing nearly 38% of its customer base. More than 147,000 Entergy users are still waiting for their lights to come back on, or roughly 5% of the total served by the utility in LA.

NES says teams of nearly 300 line workers have been deployed around the clock to make repairs and restore infrastructure. The utility says more than 76 broken poles have already been fixed. More than 70 distribution circuits are out and are being restored. Since Saturday, crews have been operating in continuous rotations and will remain on extended 14–16‑hour shifts.

Icy conditions have limited restoration progress in its territories, according to Entergy. Overnight, temperatures dropped below freezing, hampering travel and causing additional outages in some locations. As of Monday morning, the utility reported more than 88,000 outages in Louisiana and another 55,000 in Mississippi. As of Sunday evening, transmission damage assessments show approximately 20 transmission lines, 470 miles, and 20 substations out of service across Entergy’s service area. Around 10 transmission lines and 30 substations have been returned to service. At least 400 poles, 90 transformers, and 1,460 spans of wire were damaged; more than 20 poles, 20 transformers, and 70 spans of wire have been restored so far.

Duke Energy, Southwestern Electric Power Company, and Appalachian Power Company each have just north of 30,000 customers still without electricity. Tri-County EMC, Blue Ridge Electric Cooperative, North East Mississippi EPA, and Cumberland EMC are still working to restore services for more than 20,000 customers.

Reporting from the Associated Press was used in this article.

Originally published in Factor This.