Snow load in of itself demands that we guess at what it will be - even the weather man doesn't know how much snow it will be. So it calls upon us to prepare our building for the worst.
For most buildings this is relatively easy. We have a house with plans, and likely the engineer's plans already take into account potential snow load. Even the fact that most roofs are sloped help out a lot.
Where it really comes into play are things like decks, balcony's, and porches. These are things that people many times like to try and build themselves. Unfortunately undersized framing, insufficient supports, and improper framing spans don't usually show up until sometimes years later when the snow load and other factors have had time to work.
So before you venture on your own project, or buy a home with a home owner project, contact me and I will be happy to fully inspect the situation for you.