Sawtooth Mountains

This past weekend I was lucky enough to go to Stanley and the hike to Alpine Lake and Sawtooth Lake in the Sawtooth Mountains. For my Geography lesson I am going to use the Sawtooth Mountains as an example of tectonic plates colliding.I was thrilled for my landform unit that I was able to take so many great pictures of things that I teach. There was lots of snow at the top. We were at approximately 8500'. There was pink in the snow and someone said it was a bacteria (personally, I thought it was spilled Power Aid). What causes this?