Experts have raised their estimates of the size and strength of Friday's meteor strike in Russia, NBC News reported. The new estimates, based on additional readings from a sensor network built to detect nuclear blasts, suggest the meteor released the energy equivalent of nearly 500 kilotons of TNT. That's about 30 times the power of the Hiroshima atomic bomb. "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," NASA's Jet Propulsion Laboratory said in a statement. NASA now says the Chelyabinsk object must have been about 55 feet wide with a mass of 10,000 tons before it entered Earth’s atmosphere. Searchers have been focusing on a frozen lake about 50 miles west of Chelyabinsk, where they suspect meteorite fragments made a 20-foot-wide hole in the ice. Divers explored the bottom of the lake on Saturday but have found nothing so far, according to Russian news reports.