Explosions with more power destroy blocks in a weird pattern.

If you go and put a cobble stone block at Y=15 then use following command(works for all power)(/summon Fireball ~ ~2 ~

{ExplosionPower:50,direction:[0.0,0.0,0.0]}

) Then hit it on to that block, it destroys blocks in a pattern. Should be more random to look like actual explosion.