200 in South Ontario
100 in Utah....
I know there's some in Michigan, Minnesota, Wisconsin, Washington, Oregon, South Dakota, Idaho, Montana, AK...East Coast, Tahoe area...
There's a lot more than 200 if you count people who do it exactly once.
I remember going out to Whitmore lake last March, and much to my surprise I found 3 different snow kiters, went up and talked to them, one of them was kiting for the first time getting dragged around, another one was a 10 year kiter and lived on the lake but only kited there once a year, and another guy was a semi regular but he only kites about 3 times a year.
200 is the amount of regulars, but if you count absolutely everyone it would be closer to 500.
I estimate there are about 200,000 kiters in north america and of those 75,000 snow kited at least once and 20,000 at least once a year. Even in Michigan which likes hockey more than basketball there are a lot more water kiters than snow kiters.
10,000 snowkiters in north america would be an order of magnitude guess. 100,000 seems too high and 1,000 seems to low, I don't think you can narrow it down any more than that.