My initial reaction was that it looked like a tactical nuke.  The damage radius would concur as well.  What is missing is obvious radiation burns on the victims.  It's possible IDF hit a small tactical nuke held by Hezbollah or hit a stash of radiological material.  Go look at pictures of Hiroshima and Nagasaki - the damage is far greater than Beirut.  I do maintain that anything is still possible.  Thanks for the link.