Water bombed?

Last Friday after work I was driving nortn on SE 148th, approaching Stark St. in Portland.  I heard a explosion, and my windshield was covered with water, as if a barrel of water had been shot it Jet White.

I was frightened by the noise and by the amount of water.

It was loud like a firecracker; very startling.  

It was a huge amount of water that came from the front, driver's side, and the direct hit was my front line of vision.

I saw police headed that direction when I turned off 148th, but then I saw police everywhere that night.

It had to be more than a water balloon.

Kids with a water cannon?   Were they trying to cause me to crash?  Any ideas?