I had a little trouble identifying these, as they are clearly yellow, whereas the Ball-Head Gilia described in my trusty Central Rocky Mountain Wildflowers Falcon Guide are “white and sometimes flecked with purple” (page 233). But everything else seems to fit.

This is Ipomopsis congesta, from the Phlox family (Polemoniaceae). It grows in “[d]ry, open places from the valleys and plains to the alpine zones” and “[s]everal varieties occur.”