From: Virginia, USA
I don't understand why they say they are just being seen and only in the NW. We've had them on the East Coast in Maryland for 20 some years. They are very territorial and aggressive, and aren't afraid of humans. They tend to love burrowing in the cracks of concrete sidewalks and curbs. You can tell where they are by the piles of dirt near such cracks. They always have one or two 'sentinels' paroling the area and will buzz you when you get too close. I never got stung by one, but they are so big it is difficult to miss them. I once got fed up with being buzzed and used a can of that 20 foot wasp spray to defend myself. As I sprayed it at the Giant Asian Wasp it drank the stuff, spit some out, laughed at me, and flew on
I'll see if I can find a link to a show I saw about them once.
I think the ones you saw were European Hornets. Had some make a home behind the brick on my house (Virginia). Those guys are big (1.5-2 inches). I did not find them too aggressive, annoying yes, but not too bad.
It is seldom that liberty of any kind is lost all at once -- David Hume, Scottish philosopher (1711 - 1776)