No, this isn't an Edelweiss. It is a flower that I encountered on my vacation last summer, while we were stopped at a roadside nature preserve on Lake Huron between St. Ignace and Hessel. Because of my digital camera woes, I was only recently able to recover this photo from my card.
I like to think of myself as a fairly competent amateur botanist, so the mystery of this flower has been bothering me for five months now.
The focus is a little fuzzy, and it's hard to gauge the size of the flower from the picture...but think of a buttercup or marsh marigold; the flower was similar to that in size, and maybe 10 inches tall. If you look very hard, you'll see pink veining on the petals, much like an hepatica. It was growing in the sand among the dune grasses maybe 10 or 12 feet from the water's edge.
Any specialists in Great Lakes ecology who may be reading this -- knock yourselves out. I've gone through about four regional plant identification books and haven't found anything like this.