They certainly grow in the Big Horns (saw them always in limestone), but can't remember if I saw them on the Beartooth. In my garden, it is one of the very first things to bloom. I grow it in the crevice garden (soil about 7.8)
Yes, they grow in both the Beartooth and BigHorn mtns. In the high elevations of the Beartooths, they grow in granite and often bloom when the surrounding landscape is still covered with snow. Out of the thousands of plants I've seen, only the ones in the photos had pure white flowers.