I did know that, i was more surprised by the brightness

Just do a quick search for “mushroom cloud”, and you’ll find that all this combined is nowhere near what a nuke would look like.

The mushroom cloud formed from a small nuke like little boy (small by modern standards) reaches up to about 8 km. that’s close to cruising altitude for an airliner. The reason the cloud from a nuke “mushrooms” in a different way than conventional munitions is that the intense heat is causing enough hot air to rise to form a literal cloud when it reaches high enough that the humidity condenses. This can even cause radiative rain shortly after the bomb has gone off.

The fireball of Little Boy is estimated to have been almost 400 m in diameter with a surface temperature approximately equal to that of the sun, and every building within about 1.6 km was instantly completely destroyed.

It is difficult to comprehend just how much more powerful even a small “tactical” nuke is than any conventional weapon. There’s a reason soldiers that were shown blast tests of them during the Cold War have told stories of breaking down crying at the sight, because they just couldn’t fathom what they were seeing.

There was no nuke blowing up here.