"Extremely dangerous" mile-wide tornado spotted in Texas

A mile-wide tornado touched down in north-central Texas as a storm system swept through with large hail and damaging winds, the National Weather Service said, promising more severe weather on Monday.

The storm knocked out power to more than 30,000 people in Texas, according to online reports compiled from local power companies. Austin Energy reported the most affected, with 7,600 without power.

After moving through the town of Rio Vista, the tornado moved east into rural parts of Johnson County, Emergency Management Director Jamie Moore told NBC News. The tornado was about a mile wide when it was first spotted, he said.

The twister was spotted about 10:44 p.m. near Covington and near Cleburne State Park, about 25 miles south of Fort Worth, according to the weather service. "This is a particularly dangerous situation," it said.