Insect and Spider Identification: Ant?/Wasp? Identification Help!, 1 by KevinSugia

KevinSugia wrote:
I was out hiking in an area called "Upper Bidwell Park" up in Chico, CA, when I stumbled upon this insect or rather a large swarm of them. There were a large number of these coming out of a hole in the ground. To clarify what is shown: they have a jet black head and thorax and a completely orange abdomen with no visible stripes or markings, and are ~25mm in length.

My first thought was maybe it was the departure of new queens from a large species of ant, but not a SINGLE one of these insects around this hole was without wings and there were very many of them. My next thought was some kind of wasp such as a "Forest Spider Wasp" or "Fire-Tailed Mud-Nesting Wasp" but as far as I can determine from online searching Forest Spider Wasps are solitary and Fire-Tailed Mud-Nesting Wasps are found in Australia rather than California.

Would love some help in figuring out what exactly these are. Thanks!