I just saw an estimate of the force of this, placing the yield at around 300 kiloton. That's roughly nineteen Hiroshima bombs - until they have found some of the debris of the actual rock, and the place where the impact happened, it's simply a crude guess though. It looks like it went up in air and did not strike the ground in anything like one piece
- I would guess this Ural mountains meteorite could have been maybe five to ten meters across before it finally broke up and exploded, but that's a totally unscientific guess, just working from scientists' reported estimates of similar larger and smaller objects that have hit pay dirt.
For comparison, the Barringer Crater in Arizona, 1.200 meters wide, is supposed to have been shaped by a 50 meter-wide rock, a hit equal to ten megatons of TNT. The Tunguska event would have been two or three times as powerful but there was no real crater there, the thing exploded in the atmosphere, close to the surface of the earth.