Hello everyone, I'm Dutch but finished high school in Calgary, Alberta and so I applied to universities in the UK with my Alberta High School Diploma. Basically every university I contacted considered this the same as the OSSD. Except some of the colleges in Cambridge. Oxford is happy to have you for an interview though with anything above an 80% average (for engineering science at least), considering you have a good personal statement of course. They considered this the same as A grades in the A-levels, although I'm curious what will happen with the new A* grades.
I submitted al of my academic courses on UCAS, English 20-1 and 30-1, Math 30P and 20P, Calculus, Biology 20 and 30, Chemistry 20 and 30, Physics 20 and 30. I don't they really care if you put PE on and things like that.
I applied to Oxford, Imperial College, University College London, Bath, and Edinburgh. I got accepted at the last two and I'll be starting in Edinburgh in September. I applied to all of the Mechanical Engineering MEng programs, except for Oxford where they only offer Engineering Science. I had an 89% average so McGill rejected me as well. In my opinion the don't think to highly of the 12 year Canadian high school program here in the UK although I'm convinced that the 3 A-level courses most people take in England isn't much more in depth than Alberta courses at least, this is from speaking to a number of people who have done A-levels, and someone I know who already studies in the UK from Alberta.
As for skiing or boarding, Sunshine Village (45 minutes from Banff, 90 from East Calgary) offers the marmot card gives you discounts if a season pass is not worth it.
If there's any questions which I might be able to answer, shoot away.