Here is a video from Nasa explaining how the Asteroid is tracked; http://www.nasa.gov/multimedia/videogallery/index.html?collection_id=77341&media_id=119025761
I have heard reports from storm chasers of multiple Tornadoes in Oklahoma and more aftershocks were felt as well.
Here is a great video from Storm Chasers in Oklahoma, this was filmed yesterday. You can see the hail on the ground. At 2:40 minutes in you see the Chaser talk about his car that flipped over because his steering wheel locked up on him.
Courtesy of Extremetornadotours.com on youtube.