A deadly ice storm pummelling parts of the southern US this week has disrupted travel and prompted widespread power outages in Texas.
US airlines have cancelled more than 2,300 flights, with airports in Dallas and Austin being the most impacted.
Dozens of car crashes on slick roads were reported due to the bad weather, killing at least six.
Freezing rain and ice accumulations are expected across the region until Thursday.
In Texas alone, more than 340,000 people were without power as of Wednesday evening, with nearly half of the outages in and near the city of Austin, according to poweroutage.us.
The National Weather Service said the "prolonged and significant" ice storm was continuing cross much of the southern Plains and mid-south.
The storm has brought a mix of freezing rain and sleet to south-central parts of the US, spreading from Tennessee to Texas, since Monday. More than 12 million people, including in Dallas, Fort Worth, Little Rock and Memphis were under an ice storm warning.
The agency added that parts of Texas, as well as Louisiana and northern Georgia could experience flash flooding on Thursday due to heavy rain.
This weather phenomenon is caused by an Arctic cold frontal passage making its way south, where it is being confronted with warm and moist air from the Gulf of Mexico.
On Wednesday morning, Dallas issued an ice storm warning, telling drivers that "travel will be nearly impossible" through the evening and into Thursday.
Both Dallas and Memphis cancelled classes on Wednesday due to the hazardous road conditions. In Memphis, the winter weather delayed the start of the funeral for Tyre Nichols, the man who died last month after being beaten by police officers.
Emergency crews in Texas have responded to hundreds of collision calls since Monday, some of which have been fatal. Three men were killed in a crash near Brownfield, south-west of the Texas city of Lubbock, according to the state's Department of Public Safety.
One person in Austin was killed in a car pileup on Tuesday, local authorities said. Another 45-year-old man died on Monday in Arlington after his SUV slid into a highway guardrail, while a student died in a rollover crash in Wolfforth, according to local outlet KCBD.
A 49-year-old woman was also killed while driving on an icy road north of Eldorado, Texas officials told CNN.
Several local police departments have urged motorists to drive carefully. The Dallas Police Department asked people to make sure their tyres are inflated, to slow down on icy roads and to avoid using cruise control.
Texas Governor Greg Abbott also asked motorists to "stay off the roads if possible". Arkansas Governor Sarah Huckabee Sanders declared a state of emergency due to the icy conditions.