from above link:

"The estimated size of the object, prior to entering Earth's atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor's airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada."