Big ice storms in Texas do happen, but not all that often. They're about as frequent as University of Alabama football losses. And, just like Bama fans when the Tide falters, Texans often aren't quite sure what to do when ice attacks.
One thing not to do is drive. Really...it doesn't matter if you're a commercial driver in a four-wheel-drive Subraru Outback with new snow tires. No amount of technology or skill can defy the laws of physics. Driving on ice is deadly.
The best thing to do, if you can, is to stay inside and let the mayhem occur without you.