We watched this wasp drag a spider toward its hole for a good half an hour.
The surface is a coarse dirt, wet from snow melt, next to a small paved trail at about 5,500 feet. Because this trail segment is in trees, the light was not ideal.

These wasps were numerous along the trail, busily hunting on the ground.

I'm guessing spider wasp from other images and text in the guide.


Here are separate images of the spider prey alone:


And here's another individual of the same spider species we saw later on a different trail segment. It had been paralyzed, and we saw a wasp within a few yards.