What you’re describing is the difference between a detonation and deflagration. Explosions are usually extremely regular in shape unless if obstructed in some w

What you’re describing is the difference between a detonation and deflagration. Explosions are usually extremely regular in shape unless if obstructed in some way due to the way shock waves propagate in open air. And the Beirut explosion wasn’t just one detonation. There were two explosions, with a large fire and small detonations prior to the largest detonation. In all of the videos you can see a huge plume of smoke before the final detonation, as well as fire and smaller explosions if the video was close enough.