That's a great idea. A lock screen widget could work really well here, showing the relative elevations of your buddies. You'd have to take your phone out - but you wouldn't have to take your gloves off!

Would also think about ways in which the app could indicate the elevation of others without having to stop, remove the gloves, picking the phone from my pocket, looking at the screen, and putting everything back on every time.

Maybe having different kinds of (infrequent) beeping in specific cases: - when I'm last - when I'm first

This could get old quite quickly thought, just a thought.