I was under the impression that code in very snowy climates dictated a steeper pitch so that snow load would slide off largely of it’s own accord.
I’m in North Carolina, not known for big snowfalls but it does happen about once a decade with those “white hurricane” stalled out nor’easters, they just sit there off Cape Hatteras pumping it in off the Atlantic. Usually more than a foot and I’ve seen close to three before over my nearly five decades.
It’s heavy, wet snow too, so roof collapse can be an issue. It doesn’t enter anybody’s minds outside the mountain counties that all that snow could pose a threat. Flat roofs on the coast are especially prone.
I’m sure the building codes require a minimum, but I have no idea what it might be.