Turned out our wasps are called bald-faced hornets. This is what Wiki says about them: Bald-faced hornets are protective of their nests and will sting repeatedly if the nest is physically disturbed. They are more aggressive than both the wasps normally called yellowjackets and members of the Vespa genus, and it is not considered safe to approach the nest for observation purposes. The bald-faced hornet will aggressively attack with little provocation.
Here is a close up that sent shivers up my spine as I pictured Nick heading out to the nest with nothing more than a ski jacket, long pants and a can of spray, with my brother beside him in shorts and a polo shirt! Perhaps we should have called in the professionals, but thankfully they weren't stung. We read where one nest can hold up to 600 hornets. 600?? Yikes!
Below are a few more pictures of the paper nest which we removed once we were certain the spray worked and there was no more activity.