l was wondering what is the least amount of snow you would need to go ski or snowboard without scratching anything? What should the base be?

A lot has to do with the snow condition rather than the base. You could have a 5 foot base, but it could be really icy. Or you may have the snow over groomed and have tiny stones and debris. Anything over a foot should be okay, but really, do not worry about scratching your board, it is part of snowboarding. What do you think railslides do to the bottom?

dont worry we will get plenty of snow this year well atleast l will in toronto but the resorts wont open with anything less than the minimum

if you're snowboarding at a mountain i'm guessing that the mountain would open as soon as they knew the conditions were good enough to snowboard on without doing any real damage.
if you're such free riding, you will have to use your own judgment l guess. haha.

powder is ok so about 1-2 feet of powder and for packed and groomed prob like 3 feet

l would have to say atleast 2 feet (but thats if its packed powder) and if it is powder..mabye a foot?