Texans in more than 340,000 homes and businesses braced for near-freezing temperatures without power Wednesday and more than 2,300 flights were canceled amid an unrelenting blast of treacherous, icy conditions and brutal cold that has left at least six dead.

The winter weather system, now in its third day, has swept from Minnesota deep into Texas.

Wrecks on slippery roads have been reported in Texas, Arkansas and other states across the region all week.

"We really cannot emphasize this enough: DO NOT BE ON THE ROADS," the National Weather Service office in Fort Worth tweeted Wednesday. "They are going to virtually be impassable through today and tonight."

Power outages were expected to last 12 to 24 hours in the Texas state capital as ice brought down power lines and tree limbs, Austin Energy warned. The city’s community-owned electric utility said its crews were facing icy roads and frozen equipment, which made it "difficult to provide estimated restoration times."