Complex sentence: The bomb created a fireball of about 8 kilometers, raising at 1000 km/h, a deadly mushroom that reached 60 kilometers in less than 8 minutes.
Split into simpler sentences: The bomb created a fireball of about 8 kilometers in diameter. A deadly mushroom cloud that exploded at the speed of 1000km/h reached a height of 60 kilometers in less than 8 minutes.