No doubt it would be very visible on the clouds.LOL, I think you would need to get some sort of permission to fire that thing up.
You could do a hell of an advertisement for someone, just write on the clouds "Come here for whatever" LOL ;D I wonder if you could get a guiness entry for the most powerfull scanner... Or it would be cool to put that in your yard , hooked to a computer and motion detectors.And when a burglar gets caught by the motion sensors a recording would say "Halt! You have been targeted by the most powerful lazor alarm system, surrender or be burnt!"
The possibilities are endless.You can even make a more efficient laser popcorn machine than the 3x16x diode one
I wonder what is the yag being pumped with though :-/