WWFD? (What Would FABO DO??)

When I had my old stick built garage roofed, I used galvanized metal. Thought the snow would fall right off. I was wrong. it has a pretty fair pitch.......such that with metal, you need "sticky" tennis shoes to not slide off. I "guess" what happens is that a light snow freezes to the roof, and makes a "base" that won't slide until considerable warming.