Probably white-faced hornets, the curse of the Canadian bush.
Yellow-jackets are a mere annoyance, comparatively.
Bald faced hornets in the South will leave you alone unless you antagonize them. But them yeller jackets are just looking for a reason to gang up on you.
As bad a North American hornets are, I have heard that Japanese hornets are like Godzillas with stingers..................All you have to do is come near the nest, like 50 feet away and they will attack en masse.................