Bobby,

Great photo. I have been calling this a Mariposa Lily, but some use Sego Lily. It should have grass-like leaves and stem and vase-like flowers (I can't be sure from the pic.) "Mariposa" is Spanish for "Butterfly" and "Sego" is a Shoshonean word for "edible bulb". Yours is probably Calochortus gunnisonii. Nice site at www.swcoloradowildflowers.com/White%20Enlarged%20Photo%20Pag>>>
Cheers (I expect a reference in the guide for this),
Mike

I don't know the species, but it is in the genus Calochortus. There are quite a few species (50+) in this genus in the intermountain west. There may be the Gunison's Mariposa Lily.

Only about three species of this genus in Colorado. Probably C. gunnisonii as Mike said.

Mariposa Lily is correct, beautiful!