Yellow jackets live in the ground but they don't fit the description. Could it be a hornet? Do they sting? Can you post a photo?

I cannot post a photo because I am away for school. Normally when you walk over to that area they fly in front of you. I first thought they were hornets but I'm not sure.

This past summer when I was working on a research project in some wastebeds I came across a similar species that had set up colonies in a sandy washout-type area. One week they wern't there and then the next week a massive colony had apeared out of nowhere. They fit the exact description of your insects.

We had never seen anything like them. We managed to kill some of them and took a couple bodies to an entomologist at our college. They were identified as Giant Cycada-Killers. Apparently they appear very aggressive if you get near their burrows, but very rarely actually attack animals or humans. This is fortunate, as they look like something out of a horror flick. The first one I saw I actually mistook for a hummingbird- no exaggeration!

Google Giant Cycada Killers and see if it matches your insects. If so, you probably don't have a problem. They look fearsome (very much so) but I worked almost all summer amongst their burrows and was never attacked or stung. As far as I can tell, the are essentially harmless except to other insects.

Maybe they are some huge ground wasps? Sometimes we get those, they are MEAN! I was chasing my chicken back into our yard one evening, it was getting dark and all of a sudden my leg was on fire. One of them must have stung me, I got a huge welt. Usually the raccoons dig up the ground nests and expose the wasp like nesting chambers and stuff.

Most likely bumble bees, but they could also be bald face hornets.

Likely to be bumblebees. Bald-faced hornets don't nest in the ground.