(Bloomberg) -- Texas will face a fourth day grappling through an ice storm that has caused power outages, grounded flights and triggered deadly accidents on slippery roads.

Cold has gripped the landscape across northern and central Texas, as well as parts of neighboring Arkansas, Mississippi and Tennessee since the storm swept into the region on Monday. Ice has knocked down trees and power lines, and created havoc for transportation through the region.

“Today is the last day and after that things should be improving,” said Bob Oravec, a senior branch forecaster at the US Weather Prediction Center. “About a half inch of ice is across northern and central Texas and that is a lot of ice — it causes issues with the power grid.”

The ice storm is providing a painful reminder of how the southern US isn’t immune to extreme winter weather. The latest cold snap comes almost two years after a deadly storm in Texas caused the electrical system to fail, leaving millions of residents without power for hours and even days. State officials have made a number of reforms to the grid since then, including reinforcing natural gas plants and pipelines to withstand extreme weather.

As of early Thursday, more than 407,000 customers in Texas were without power, along with nearly 100,000 more in Arkansas, Mississippi, Tennessee and Florida, according to PowerOutage.us. 

Texas Governor Greg Abbott has said there is plenty of electricity in the state’s grid and blamed outages on falling trees, according to Tweets. He has also urged people to stay off the roads.

At least 8 people have died in accidents since the storm began, according to the Associated Press.

The ice has also prompted airlines to ground planes. More than 700 flights into and around the US have been canceled, with the majority of them in Dallas, according to FlightAware, an airline tracking company.

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