An area stretching from Texas to Tennessee braced Wednesday for the possible arrival of freezing rain and snow even as some other parts of the U.S. hit by the plunging polar vortex this week began to shake off its icy effects.

The plunging polar vortex brought subfreezing temperatures Tuesday to some of the southernmost points of the U.S., threatening to dump snow on parts of Texas and Oklahoma in coming days and contributing to a power outage in Virginia's capital that made the water unsafe to drink.

In Indiana, the National Guard was activated to help stranded motorists. The storm was expected to reach the Mid-Atlantic states on Monday and bitter cold temperatures could grip much of the East Coast deep into the South.