chopper attack

So I'm yakking across lake union, up near gas works park, checking out all the decorations they've already started to put up, and along comes an army helicopter, one of the big jobbies with two rotors. He's maneuvering slowly along the waterway, about 4-500 feet up. They make a slow circle around the north end of the lake, I wave up to a guy hanging out the side, he waves back, they fly off towards the arboretum.

I start working my way back towards the dock at the south end, having gotten in my 10 mins of heavy breathing, and what I think was the nifty sight of the day. The chopper is back over the north end, more over gasworks park than the water this time, and I hear some popping sounds. I look, and someone on the ground is shooting fireworks at the chopper. They're exploding about 100-150 feet short, but it's still so weird. I suspect downdraft would keep any consumer level item from getting too close, but who knows. It's so loud when that thing was directly overhead, much less inside, who knows if they even heard it. They came back out over the lake and dipped down to about 100 feet from the water, kicking up a fair bit of spray, and causing one of the float-planes to abandon his original take-off vector (he ended up going the opposite direction for take-off, then coming around to his final heading over cap hill).