Alan Bellows via Damn Interesting:

‘Despite the cloudy weather, the flash of light was visible as far as 1,000 kilometers distant, though the sound of the blast would not reach that far for forty-nine minutes, in the form of an indistinct, heavy blow. The giant fireball reached from ground-level to about 34,000 feet into the air, violently releasing 3800 times more explosive energy than the Hiroshima bomb —equivalent to fifty million metric tons of TNT. One hundred kilometers from ground zero the heat would have inflicted third degree burns. Atmospheric focusing produced areas of destruction hundreds of kilometers from ground zero, including wooden structures which were completely destroyed, and some shattered windows in Finland. The explosion’s atmospheric shockwave traveled around the Earth three times before it dissipated.

The mushroom cloud which followed the blast was enormous in scale. It stretched sixty kilometers into the sky, and had a diameter of about forty kilometers. Ionization from the explosion disrupted radio communications for the better part of an hour….’