They are bad. I have stepped in them several times. That's enough to make you sick. Lots of folks think paper wasp are yellowjackets but the real deal will sting you hundreds of times if you cant get away.
Found that rubbing Jewel Weed on a sting, bite, will take it away. No swelling and it reduces the itching.
It something that I just let grow anywhere it wants as it seems to be the easy and the quickest thing handy.
I found them a few times before, dropped my detector and ran . But I would take another run-in with them over the Poison Ivy that was unforgettable...that was only once. Hope you get back out there soon.
If they were ground hornets like I am guessing, go back early AM and start your lawn mower over there entrance and stand there and enjoy the carnage.
Or molten aluminum cast the hole.
Ants, hornets, who cares!
Working in the woods for my career, I found that yellowjackets like to have a 180 degree defense perimeter, so the nests are located at bases of trees, bushes. And they have guards, roaming around, looking for guys like you, to nail...!
Look for any activity, then steer away...!